How to Sign a PDF for Free on Any Device

Someone sends you a PDF to sign. A lease agreement, a freelance contract, a permission form, a tax document. You need to add your signature and send it back. This should take sixty seconds.

Instead, you discover that the PDF tool you used last time now requires a paid subscription. You try another tool and it wants you to create an account. You try a third and it watermarks the output. Fifteen minutes later, you still have not signed the document.

The good news is that every device you own already has the ability to sign PDFs for free, either through built-in tools or through browser-based options that require no installation and no account. This guide covers every major platform with step-by-step instructions so you can sign anything, anywhere, in under a minute.

Mac: Sign with Preview (Built-In)

Every Mac ships with Preview, and Preview has a fully capable PDF signature tool that most Mac users never discover. It is the fastest way to sign a PDF on any platform.

1. Open the PDF in Preview. Double-click the file, or right-click and select Open With > Preview. Preview is the default PDF viewer on macOS, so it should open automatically.
2. Open the Markup toolbar. Click the pen-tip icon in the toolbar, or go to View > Show Markup Toolbar.
3. Click the Signature button. It looks like a cursive signature. If you have not created a signature before, it will prompt you to create one.
4. Create your signature. You have three options:
   • Trackpad: Draw your signature directly on the trackpad with your finger. This is surprisingly natural and produces a realistic result.
   • Camera: Sign a piece of white paper and hold it up to your Mac's camera. Preview captures the signature and removes the background automatically.
   • iPhone or iPad: If you have an iPhone or iPad on the same iCloud account, you can sign on the phone's screen and it transfers to Preview instantly. This produces the most natural-looking signatures because you are writing with your finger on a touch screen.
5. Place the signature. Click where you want the signature on the PDF. Drag the corners to resize. Preview places it as an annotation layer, so you can reposition it as needed.
6. Save. Press Command+S. The signature is embedded in the PDF. Send the file back.

The best part: Preview saves your signature for reuse. The next time you need to sign a PDF, skip step 4. Your saved signature appears in the dropdown and you just click to place it.

Preview also handles text fields, dates, checkboxes, and basic annotations. For most signing tasks, you never need to leave Preview.

Windows: Sign with Microsoft Edge or Adobe Reader

Windows does not have a Preview equivalent built into the OS, but two free options handle PDF signing without any purchase.

Microsoft Edge (Built-In)

1. Open the PDF in Edge. Right-click the file and select Open With > Microsoft Edge. Edge has been a capable PDF viewer since 2020.
2. Click "Add signature" in the toolbar. You will see options to type, draw, or upload an image of your signature.
3. Draw your signature. Use your mouse, trackpad, or stylus to write your signature. On a Surface device or any touchscreen Windows laptop, you can write directly on the screen for a natural result.
4. Place and save. Click to position the signature on the document, resize as needed, and save the PDF.

Edge's signature tool is simple and effective for self-signing. If you need more control over field placement or want to fill complex forms, Adobe Acrobat Reader offers more features.

Adobe Acrobat Reader DC (Free)

1. Download Adobe Acrobat Reader DC from Adobe's website. It is free and always has been. Do not confuse it with Acrobat Pro, which is the paid version.
2. Open the PDF and click "Fill & Sign" in the right panel (or under the Tools menu).
3. Click "Sign yourself" then "Add Signature." You can type your name in a script font, draw freehand, or upload an image of your handwritten signature.
4. Click to place the signature anywhere on the document. Add dates, text fields, and checkboxes as needed.
5. Save. The signed PDF is ready to send.

Adobe Reader saves your signature for future use, so subsequent signings are a single-click operation. The Fill & Sign feature is genuinely free with no document limits, no watermarks, and no time restrictions.

iPhone and iPad: Sign with Markup

iOS has built-in PDF signing that works across multiple apps. You do not need to download anything.

From the Files App

1. Open the PDF in Files. Navigate to the file and tap to open it.
2. Tap the Markup icon (pen-tip icon in the toolbar).
3. Tap the + button and select "Signature."
4. Sign with your finger or Apple Pencil. The signature is captured instantly. Tap Done.
5. Position and resize the signature on the document. Tap Done again to save.

From Mail

If someone emailed you the PDF, you can sign it without saving it to Files first:

1. Tap the PDF attachment in the email to open it.
2. Tap the Markup icon.
3. Add your signature as described above.
4. Tap Done, then tap Reply to send the signed document back immediately.

iOS remembers your saved signatures across apps, so you create the signature once and reuse it everywhere. If you own an Apple Pencil, the signatures are practically indistinguishable from pen on paper.

iPad users get an even better experience because the larger screen gives you more room to write naturally. For frequent signers, an iPad with Apple Pencil is the best hardware combination for producing authentic-looking digital signatures.

Android: Sign with Google Drive or Adobe Reader

Android offers two free options. Google Drive is pre-installed and supports PDF annotation: open the PDF, tap the edit icon, and draw your signature with the pen tool. For a more polished experience with saved signatures, install Adobe Acrobat Reader from the Play Store (free). It includes the same Fill & Sign functionality as the desktop version: create a signature once, save it, and tap to place it on any future document.

Any Device: Sign in the Browser

If none of the above options work for your situation, or if you want a consistent experience across every device, browser-based tools are the universal fallback. They work on any operating system with a modern browser.

DocSigner is a free browser-based PDF signing tool that runs entirely on your device. Your PDF never leaves your computer or phone. There is no account to create, no upload to a server, and no limit on how many documents you sign.

1. Open DocSigner in any browser (Chrome, Safari, Firefox, Edge).
2. Load your PDF. Drag and drop, or use the file picker.
3. Create your signature. Draw with your mouse, trackpad, or finger (on touch devices). You can also type your name in a signature font.
4. Place the signature on the correct page and position. Resize as needed.
5. Add other fields if needed: date, text, checkboxes.
6. Download the signed PDF. Done.

The browser approach has a specific privacy advantage worth highlighting. When you use a cloud-based signing service like DocuSign or HelloSign, your document is uploaded to their servers for processing. That means a third party has a copy of your contract, tax form, medical document, or whatever you are signing. DocSigner processes everything in the browser using JavaScript, so the document stays on your device from start to finish. For a detailed comparison of free signing tools and their privacy characteristics, the free document signing tools guide covers the full landscape.

Creating a Reusable Signature

Signing one document is easy. Signing your twentieth document of the month is tedious if you have to re-draw your signature every time. Here is how to set up a reusable signature on each platform:

For the cleanest reusable signature, sign your name with a black pen on white paper, photograph it, and remove the background to save as a transparent PNG. Keep this file in cloud storage for access from any device. When drawing digitally, use a stylus or finger on a touch screen (mouse-drawn signatures look unnatural), sign larger than you think you need (you can always scale down), and use black ink for best contrast.

Legal Validity of Electronic Signatures

A common concern is whether a PDF signed with a free tool is legally valid. The short answer: yes, in nearly all cases.

In the United States, the ESIGN Act (2000) and the Uniform Electronic Transactions Act (UETA) make electronic signatures legally equivalent to handwritten signatures for most transactions. The EU's eIDAS regulation provides a similar framework across European countries. Canada, Australia, and most other developed nations have comparable laws.

What makes a signature legally binding is not the tool but four elements: intent to sign, consent to do business electronically, association of the signature with the document, and retention of the signed record. A signature created in Preview, Adobe Reader, or DocSigner satisfies all four. The narrow exceptions are Qualified Electronic Signatures (QES) under EU eIDAS requiring a certificate authority, certain government filings with specific format requirements, and notarized documents requiring a notary's digital certificate.

For the vast majority of signing needs (contracts, leases, NDAs, invoices, HR documents), any electronic signature from any tool is legally valid. For more detail on when paid services offer meaningful advantages, the DocuSign alternatives comparison breaks down the features that justify a subscription.

When You Actually Need a Paid Service

Free tools cover self-signing perfectly. Paid services earn their cost when you need features beyond placing a signature on a document:

• Multi-party signing workflows where documents route to multiple signers in sequence with notifications.
• Tamper-evident audit trails with cryptographic seals for legal disputes and regulatory compliance.
• Templates with reusable fields for sending the same contract to many clients.
• API access for programmatic document generation and signing in your applications.

If none of these apply to you, a free tool handles the job completely. Most individuals and small teams fall into this category.

Quick Reference: The Fastest Method per Device

No matter what device you are on, you can sign a PDF for free in under a minute. The tools are already on your device or one browser tab away. There is no reason to pay for a subscription, create an account, or upload your confidential documents to a third-party server. Open the PDF, add your signature, save, and send.