# How to Sign a PDF on Any Device: Windows, Mac, iPhone, Android and Chrome, Free

To sign a PDF free, open it in a tool that can place a signature, add yours, save a copy. The free routes on Windows, Mac, iPhone, Android and Chrome, compared.

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- **Canonical URL:** https://dothecalculation.com/blog/files/how-to-sign-a-pdf
- **Category:** Files & PDFs
- **Author:** Do The Calculation Team
- **Published:** 2026-09-30
- **Reading time:** 20 min read
- **Publisher:** Do The Calculation (https://dothecalculation.com)
- **Methodology:** https://dothecalculation.com/methodology

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## How to sign a PDF: the short answer

To sign a PDF for free, open it in a program that can place a signature on the page, add your signature, and save a new copy. Every current device has one built in: Preview on a Mac, Markup and the Files app on an iPhone or iPad, the PDF viewer in Microsoft Edge on Windows, Chrome’s own PDF viewer on any computer, and the Gallery app on a Chromebook. Adobe Acrobat Reader, which is free, does the same on Windows, Mac, Android and iOS. None of them needs a printer or a scanner.

What differs is the details: whether the tool can fill in the form fields the PDF already has, whether it keeps your signature for next time, whether it can put initials on every page, whether your file stays on your device or goes into a cloud account, and whether the signature ends up as part of the page or as a mark someone else can move. This guide compares them device by device, with the menu paths from each maker’s own help pages as we read them on 30 September 2026, and explains what you are actually producing when you sign this way.

Tool: [Sign a PDF in your browser, without uploading it](https://dothecalculation.com/tools/sign-pdf) — Place your signature, initials, the date and text on any page, fill in the form fields, and download the signed copy. Works on any device with a browser; the file never leaves it.

Tool: [Make a signature image first](https://dothecalculation.com/tools/signature-maker) — Draw it, type it in a handwriting font, or photograph the one you sign on paper and remove the paper. Download a transparent PNG or SVG.

## Which free tool to use on each device

The table lists the tools built into each system, plus the free Adobe Reader and this site’s browser tool. The path column is taken from the vendor’s own support page; the last column says whether that page states where your file goes. Where it does not, we say so rather than guess, and where the answer is our inference from how the tool works, it is marked as such.

**Free ways to sign a PDF, with paths from each vendor’s help page (read 30 September 2026)**
| Device | Tool | Path to sign | What it places | Where the file goes |
| --- | --- | --- | --- | --- |
| Mac | Preview | Show Markup Toolbar, then Sign; create with trackpad, camera or iPhone/iPad | Your signature drawn on the page | Stays on the Mac (inference); saved signatures sync through iCloud Drive |
| iPhone, iPad | Files form view | AutoFill button to fill fields; Add button, then Add Signature | Signature on the page | On the device (inference) |
| iPhone, iPad | Markup (Mail, Notes, Photos, Preview) | Markup button, Add button, Add Signature | Signature on the page | On the device until you send it (inference) |
| Windows, Mac | Microsoft Edge | Open the PDF in Edge, Draw, write your name, Save; Add text for typed text | Ink drawn over the page | Stays on your computer (inference) |
| Windows, Mac, Linux, ChromeOS | Google Chrome | Draw, Pen, sign, Done; Download “With your changes” | Ink drawn over the page | Stays on your computer (inference) |
| Chromebook | Gallery app | Signature button, draw, Place signature, Save | Drawn signature, kept for reuse | On the Chromebook (inference) |
| Windows, Mac | Adobe Acrobat Reader (free) | Sign icon or Tools, Fill & Sign; Type, Draw or Image; Apply | Signature that becomes part of the PDF on save | Local (inference); a saved signature goes to Adobe’s cloud if you sign in |
| Android, iOS | Adobe Acrobat Reader app | Fill & Sign, Signature, Add signature | Signature, flattened on save | Saved on the device, synced to your Adobe account when online |
| Android | Google Drive app | Annotate button to draw; Edit, Form Filling for fields | Ink drawn over the page | The file is in your Google Drive |
| Any browser | Sign PDF on this site | Open the PDF, Signature, place, Sign and download | Signature drawn into the page, or a stamp | Stays in the browser tab |

Sources: Apple’s Preview guide (https://support.apple.com/guide/preview/fill-out-and-sign-pdf-forms-prvw35725/mac) and iPhone guide (https://support.apple.com/guide/iphone/fill-forms-sign-documents-create-signatures-iph1d3607e5c/ios); Microsoft’s Edge PDF reader documentation (https://learn.microsoft.com/en-us/deployedge/microsoft-edge-pdf); Google’s Chrome help (https://support.google.com/chrome/answer/16215622) and Chromebook help (https://support.google.com/chromebook/answer/12453461); Adobe’s Reader help (https://helpx.adobe.com/reader/desktop/sign-pdfs.html) and mobile help (https://helpx.adobe.com/acrobat/mobile/e-sign-documents/fill-sign.html); Google Drive help (https://support.google.com/drive/answer/13207179).

> **Two routes that do upload the file** — Adobe’s online signing page says plainly that “your file will be uploaded to Acrobat web” and that you must sign in (https://www.adobe.com/acrobat/online/sign-pdf.html). Files by Google on Android saves an annotated copy by uploading it: “When you save a copy, it’s uploaded to your Google Drive” (https://support.google.com/files/answer/15949407). Neither is wrong, but for a contract or a medical form it is worth knowing before you press the button.

## What you are actually producing

Nearly every free route above produces the same kind of thing: a picture or drawing of your signature placed on the page. In law this is usually a simple electronic signature, and for most everyday agreements it is enough. It is worth knowing the three forms it can take in the file, because they behave differently once the PDF leaves your hands.

- Drawn into the page. The signature becomes part of the page content, like ink on paper. It prints everywhere and cannot be dragged off in another viewer. Adobe’s mobile app says of its signatures that the PDF “flattens on save and cannot be edited or unsigned afterward”. This site’s Sign PDF does this by default.
- Added as an annotation. Ink from Edge, Chrome or the Drive app, and stamps, sit in a layer on top of the page. They print and look the same, but many PDF readers let anyone select, move or delete them. Fine for a quick return, weaker for a final contract.
- A certificate-based digital signature. This is different in kind: a cryptographic seal made with a certificate, which shows whether the file has changed since signing. Word’s Signature Line creates one inside a Word file (Microsoft says the document “becomes read-only to prevent modifications”), Acrobat can create them in PDFs with a certificate, and Microsoft says Edge can view and validate them but does not say it can create them.

Google’s own Chromebook help adds a fair warning about the drawn kind: its signature feature “is for convenience and doesn’t provide signature verification or security”. That is true of every image signature. What makes it hold up is the context, such as the emails around it, which [Are electronic signatures legally binding?](/blog/business/are-electronic-signatures-legally-binding) explains country by country.

_[Figure: Three ways a signature can sit in a PDF — What the recipient can do with each, once you send the file.]_

## How to sign a PDF on Windows

Windows has no separate signing app, but Microsoft Edge, which comes with Windows, opens PDFs by default. Microsoft’s documentation for IT administrators lists the reader’s features and says inking “comes in handy to take quick notes for easy reference, sign, or fill out PDF forms” (https://learn.microsoft.com/en-us/deployedge/microsoft-edge-pdf). It also lists basic form filling, text notes and highlighting, and says forms that rely on JavaScript and the old XFA format are not supported.

- Right-click the PDF and choose Open with, Microsoft Edge (it is usually the default already).
- If the PDF has fields, click into each one and type.
- Choose Draw in the toolbar, pick a colour and thickness, and write your name with the mouse, a pen or your finger. Choose Add text if you would rather type your name.
- Choose Save or Save as, and save a copy under a new name so the original stays unsigned.

The Draw button’s name comes from the Edge team’s own announcement of PDF inking, which says you “can click or tap on the Draw button to enter inking mode” (https://techcommunity.microsoft.com/discussions/edgeinsiderannouncements/pdf-inking-on-microsoft-edge/1016006). We found no dedicated Sign button described on any current Microsoft page. A mouse-drawn signature tends to look rough; making a signature once in the [Signature Maker](/tools/signature-maker) and placing it with [Sign PDF](/tools/sign-pdf) gives a cleaner result, keeps it for next time, and adds dates and initials.

Adobe Acrobat Reader is the other common free route on Windows. Adobe’s help says: “Click the Sign icon in the toolbar. Alternatively, you can choose Tools > Fill & Sign”, then add your signature or initials by typing, drawing or choosing an image, click Apply, and click where it belongs (https://helpx.adobe.com/reader/desktop/sign-pdfs.html). It detects form fields automatically. You only need to sign in to Adobe if you want the signature saved to its cloud for reuse.

## How to sign a PDF on a Mac

Preview, the app that opens PDFs on a Mac, is one of the best free signing tools on any system, mainly because of how you create the signature. Apple’s guide gives three ways: sign on the trackpad with your finger, hold your signature “on white paper” up to the camera so it lines up with a blue line, or sign on a nearby iPhone or iPad with a finger or Apple Pencil (https://support.apple.com/guide/preview/fill-out-and-sign-pdf-forms-prvw35725/mac).

- Open the PDF in Preview. To fill fields, click one and type; if typing does not work, use the Show Form Filling Toolbar button and then the Text Box Tool.
- Click the Show Markup Toolbar button if the toolbar is hidden, then click Sign.
- Create a signature with the trackpad, the camera or your iPhone or iPad. It is saved for next time.
- Click the signature to add it, drag it into place and resize it with the handles.
- Choose File, Duplicate or Save to keep a signed copy, and send that.

Apple says saved signatures appear on your other Macs “if you use iCloud Drive”, so the signature image itself is synced through iCloud when that is on. Preview can also fill forms from your My Card in the Contacts app with AutoFill Form. We found no command in Preview that puts initials on every page at once; you add them page by page.

## How to sign a PDF on an iPhone or iPad

On an iPhone or iPad the tools live inside the apps you already use. Apple’s iPhone guide describes the form route: open the document (if asked, open it in the Files app and tap Save), tap the AutoFill button and a blank field to type, then “tap the Add button” and “Add Signature, sign your name with your finger, then tap Done”, and drag the signature where it belongs (https://support.apple.com/guide/iphone/fill-forms-sign-documents-create-signatures-iph1d3607e5c/ios). When you are done, the Menu button offers Export, Print and Share.

- For a PDF someone emailed you: in Mail, tap the attachment, tap the Markup button, add your signature, tap Done, then choose to reply to the sender, start a new message or save to Files (https://support.apple.com/guide/iphone/annotate-email-attachments-iph845853585/ios).
- For a form: open it in Files, fill the fields with the AutoFill button, then Add, Add Signature.
- In the Preview app (documented from iOS 26): open the PDF, tap Markup, tap Add, then choose a signature (https://support.apple.com/guide/iphone/annotate-a-pdf-or-image-iph73ca5c8e6/ios).

Apple notes you can save several signatures, “such as a nickname or initials”, and suggests rotating the iPhone for more space to sign. A finger on a phone screen is fiddly; if yours comes out shaky, make it once on a larger screen, or use a photo of your paper signature cleaned up in the [Signature Maker](/tools/signature-maker), then place it with Sign PDF in Safari, which runs on an iPhone like any other browser.

## How to sign a PDF on Android

Android does not have one signing tool in every phone, so the routes depend on the apps you have. Google Drive can draw on a PDF: open it in the Drive app and “at the bottom right corner, tap the annotate button” for a pen, highlighter and eraser; you can save over the original or save a copy (https://support.google.com/drive/answer/13207179). Drive can also fill in form fields: tap Edit, then Form Filling, enter your details and tap Save (https://support.google.com/drive/answer/9463834). Both work on a file that is in your Google Drive.

Chrome on Android can annotate PDFs with a pen, highlighter and eraser on Android 12 and later, according to Google’s Chrome help, though that page does not describe signing or typing text there. The Adobe Acrobat Reader app offers a complete route: open the PDF, choose Fill & Sign, then Signature, Add signature, draw it, use an image or capture one with the camera, tap to place it and tap the check mark to save. Adobe says the app works offline and that the PDF “flattens on save and cannot be edited or unsigned afterward” (https://helpx.adobe.com/acrobat/mobile/e-sign-documents/fill-sign.html).

If you would rather not put the document in Drive or install an app, Sign PDF on this site works in Chrome on Android: draw your signature with a finger, drag it into place on the page view, and download the signed copy to your phone.

## How to sign a PDF in Chrome and on a Chromebook

Chrome’s own PDF viewer on a computer (Windows, Mac, Linux or ChromeOS) now has drawing and text tools. Google’s help gives the steps: open the PDF in Chrome, “Select Draw. On the right panel, select Pen”, choose a size and colour, draw your signature, select Done, then download “With your changes” (Chromebook users select Save) (https://support.google.com/chrome/answer/16215622). Add text places typed text wherever you click.

Chromebooks also have the Gallery app, which opens PDFs from the Files app. Its help page describes a signature button: draw your signature, select Place signature, and it is saved to use in other documents. It can fill out forms and add text, and it warns that the feature “doesn’t provide signature verification or security” (https://support.google.com/chromebook/answer/12453461). The same page says you cannot add text in the Chrome browser, which conflicts with Chrome’s newer help page; Chrome’s own page describes an Add text tool, so the Chromebook page is probably older.

## Google Docs and Word: signing documents before they are PDFs

If the document is still a Word or Google Docs file, you can sign it there and save it as a PDF afterwards. In Word, Microsoft’s help suggests scanning your signature, saving it as an image and choosing Insert, Pictures, with the option of saving it with your typed name as a reusable Quick Part (https://support.microsoft.com/en-us/word/insert-a-signature-in-a-word-document). Word for the web “has no command for inserting your signature”, so there you insert the image with Insert, Picture.

Word’s Insert, Signature Line is something else: it adds a line for a certificate-based digital signature inside the Word file, after which Microsoft says the document becomes read-only. We could not confirm from Microsoft’s pages whether that signature survives when the file is saved as a PDF, so do not rely on it for a PDF. In Google Docs, Insert, Drawing, New opens a drawing canvas that includes a Scribble line tool; Google’s eSignature feature (Tools, eSignature) sends documents for signature with an audit trail page, but its help page lists it only for Workspace Individual and certain paid Workspace plans, not free personal accounts (https://support.google.com/docs/answer/12315692).

For a Word file you only need to sign, [Word to PDF](/tools/word-to-pdf) converts it in your browser and Sign PDF then signs the result, neither step uploading it.

## Step by step: signing in the browser on any device

Because a browser is the one tool every device has, here is the full route with [Sign PDF](/tools/sign-pdf), which works the same on Windows, Mac, Linux, ChromeOS, Android and iOS.

- Open the page and drop the PDF on it, or choose it. If it has a password, type it; it unlocks the file in the tab only.
- Under Signature, pick a saved signature, or draw or type one; tick Also save it on this device to keep it. It lands on the first empty signature field, fitted to it, or near the bottom of the page.
- Drag it into position and resize it from a corner. Add Initials, a Date (today by default) and any Text the same way.
- If the PDF has form fields, fill them in the form panel: text, dates with a date picker, check boxes, choices and lists.
- Under Finish, keep Lock the form on for a final copy, and leave items as part of the page.
- Press Sign and download. The copy is saved as the original name with -signed added, and Compare with the original shows the page before and after.

It places items exactly where you drop them even on pages stored sideways or cropped, which trips up some tools: on our test pages rotated by 90, 180 and 270 degrees and with cropped page areas, every item landed within 0.1 point of the drop position.

## Making a signature that reproduces well

The signature image you place is what the recipient sees and prints, so a few minutes on it pays off every time you sign.

- Size: sign large and let the tool scale it down. A signature drawn small and then enlarged shows every wobble.
- Contrast: dark ink on a transparent background. For a photographed signature, sign with a black or dark blue felt-tip on plain white paper in good light; ballpoint lines are thin and pale in photos.
- Transparency: use a PNG with a transparent background, not a JPG, so the signature does not sit in a white box over lines and text. Preview’s camera capture and the Signature Maker both remove the paper.
- Resolution: printing is usually judged at 300 dots per inch, about 11.8 pixels per millimetre. A signature printed 50 mm wide needs about 600 pixels across; 1,200 pixels covers anything up to 10 cm. If your signature looks pixelated in the PDF, the image was too small, not the PDF.
- Consistency: save the signature and reuse the same one, so your documents match. Most tools above keep saved signatures; Preview syncs them through iCloud Drive.

## Signing forms: fields versus flat scans

A fillable PDF form has fields built in: boxes you click and type into, check boxes and radio buttons, drop-down lists, and sometimes a signature field. The field keeps its value separately from the page, which is why values typed in one viewer appear in another. Preview, Edge, Chrome, Acrobat Reader, the Drive app and Sign PDF can all fill fields, and all of them struggle with forms built on JavaScript or the old XFA format, which Microsoft says Edge does not support.

Once a form is filled and signed, lock it. Flattening draws each field’s value into the page and removes the field, so the answers cannot be changed afterwards and every viewer shows the same thing. Sign PDF flattens by default and handles check boxes and radio buttons, which some flattening tools drop; Adobe’s mobile app flattens on save. Keep a form live only if someone else still has to fill in their part.

A flat scan has no fields: it is a picture of a paper form. Sign it the same way, and add text boxes for the answers and check marks for the boxes. If the scan came from photos, make the PDF first with [JPG to PDF](/tools/jpg-to-pdf), and if a page is sideways, turn it upright with [Rotate PDF](/tools/rotate-pdf) before signing, so the signature is not sideways too.

## Signing or initialling every page

Leases, loan papers and long contracts often ask for initials at the foot of each page. In Preview, Edge, Chrome and Markup that means placing the initials page by page. Sign PDF has an Every page command: place your initials once, select them, press Every page, and a copy appears in the same position on each page, with Remove copies to undo it. Text can carry page tokens, so “Initialled, page {page} of {pages}” becomes “page 7 of 60” on the seventh page. On a 60-page test document the whole job, including a summary page, took under half a second.

If only some pages need signing, you can also split them out with [Split PDF](/tools/split-pdf), sign those, and put the file back together with [Merge PDF](/tools/merge-pdf), though sending the whole signed document is usually clearer for the other side.

## Sending the signed PDF back

Save the signed copy under a new name, keep the unsigned original, and check the signed copy in a second viewer before sending it: open it in your browser as well as the app you used, to make sure the signature and any filled fields show in both. Then reply to the sender with the file attached.

Size limits are the usual snag. Gmail’s help says “for personal Gmail accounts, the limit is 25 MB”, and larger attachments are turned into a Google Drive link (https://support.google.com/mail/answer/6584). Outlook.com allows 25 MB per file (https://support.microsoft.com/en-us/outlook/sending-limits-in-outlook-com), while the classic Outlook desktop app caps internet accounts at 20 MB and Exchange defaults to 10 MB, including the message itself (https://support.microsoft.com/en-us/office/reduce-attachment-size-to-send-large-files-with-outlook-8c698842-b462-4a4c-8d53-5c5dd04f77ef). iCloud Mail allows 20 MB, or up to 5 GB with Mail Drop, which gives the recipient 30 days to download (https://support.apple.com/en-us/102198).

A signed text document is rarely large, but a scanned one can be. [Compress PDF](/tools/compress-pdf) shrinks the scanned images while the signature stays sharp, and [How to send a large PDF](/blog/files/how-to-send-a-large-pdf) covers every other route, from splitting to sharing a link. One caution: compressing or otherwise changing a PDF that carries a certificate-based digital signature breaks that signature, so compress before a digital seal is applied, never after.

## When a signature image is not enough

A signature placed with any of these tools is a simple electronic signature. For an offer letter, an NDA, a quote you accept or a form for a school, that is normally all that is needed. It is not enough when the document itself or the other party requires more:

- Documents that need a witness or notary, such as deeds and many powers of attorney, or wills, which in most places must be signed on paper.
- Government, court or tender filings that require a qualified electronic signature, a certificate from an approved provider or a national e-ID.
- Agreements where you want proof of who signed and when, such as high-value contracts; signing services keep an audit trail of email addresses, times and IP addresses.
- Documents that must show they were not changed after signing, which needs a certificate-based digital signature.

[Are electronic signatures legally binding?](/blog/business/are-electronic-signatures-legally-binding) sets out the rules in the United States, the European Union, the United Kingdom and eight other countries, including the documents that still need ink. [Are online PDF converters safe?](/blog/files/are-online-pdf-converters-safe) explains how to check whether any web tool uploads your file, and [How to edit a PDF](/blog/files/how-to-edit-a-pdf) covers changes that go beyond signing.

## Frequently asked questions

**How do I sign a PDF for free without Adobe?**

Use the tool built into your device: Preview on a Mac, Markup or the Files app on an iPhone or iPad, the PDF viewer in Microsoft Edge on Windows, Chrome’s PDF viewer on any computer, or the Gallery app on a Chromebook. Or use a browser tool that does not upload the file, such as Sign PDF on this site.

**How do I sign a PDF on my phone?**

On an iPhone, open the PDF from Mail or Files, tap Markup or the Add button, then Add Signature. On Android, the Adobe Acrobat Reader app’s Fill & Sign, the Google Drive app’s annotate pen, or a browser tool such as Sign PDF all work. Turn the phone sideways for more room to sign.

**How do I sign a PDF without printing it?**

Open it in a signing tool, place a saved or drawn signature on the page, and save a copy. Every method in this guide works without a printer or scanner.

**How do I sign a PDF someone emailed me?**

Save the attachment, open it in a signing tool, add your signature and any dates or initials, save a copy under a new name, and reply with that copy attached. On an iPhone you can do it inside Mail: tap the attachment, then Markup, then reply when done.

**How do I make my signature transparent in a PDF?**

Use a PNG image with a transparent background rather than a JPG, or draw the signature directly in the tool. Preview’s camera capture and the Signature Maker on this site both remove the paper from a photographed signature.

**How do I sign a PDF on a Chromebook?**

Open the PDF from the Files app in the Gallery app and use its signature button, or open it in Chrome and use Draw, then Pen. A browser tool such as Sign PDF also works and can fill form fields and add dates.

**Can I sign a scanned PDF?**

Yes. A scan is a picture of each page, and a signature can be placed on it like any other page. It has no form fields, so type the answers as text boxes and add check marks where needed.

**Why does my signature look pixelated in the PDF?**

The image was too small for the size it is shown at. Use a signature image at least 600 pixels wide for a 5 cm signature, or a drawn or vector signature, which stays sharp at any size.

**Is signing a PDF with an image legally binding?**

For most everyday agreements, yes: laws in the United States, the European Union and the United Kingdom accept electronic signatures, including an image or typed name used with the intent to sign. Some documents, such as wills and many deeds, need more. See the legal guide linked above.

**Can the recipient move or remove my signature?**

If it was added as an annotation, many PDF readers let them. If it was drawn into the page, as Sign PDF and Adobe’s mobile app do, it cannot be dragged off, although anyone with editing software can still alter a PDF. Only a certificate-based digital signature shows that the file changed afterwards.

Tool: [Sign your PDF now](https://dothecalculation.com/tools/sign-pdf) — Signature, initials on every page, dates, text and form fields, in any browser. The file is never uploaded.

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_Source: [Do The Calculation](https://dothecalculation.com/blog/files/how-to-sign-a-pdf). Quote freely with attribution and a link to this page._