How to Sign a PDF Online Free — Methods That Work

Signing a PDF used to require printing it, signing it with a pen, and either scanning it back or faxing it. In 2026, the whole process can happen entirely online in a few minutes — legally and for free. Here's how to do it without paying for Adobe Acrobat or a dedicated e-signature service.

What counts as a valid electronic signature?

Before the methods, it's worth knowing what's legally acceptable. In most countries, an electronic signature is legally equivalent to a handwritten one for most document types. The key legislation: the US ESIGN Act, the EU eIDAS regulation, and the UK Electronic Communications Act all recognise electronic signatures as legally binding for standard commercial and personal contracts.

The exceptions are narrow: some jurisdictions require wet signatures for wills, court filings in certain cases, and some property transactions. For everyday business documents — employment contracts, client agreements, NDAs, purchase orders — an electronic signature is fully valid.

Method 1: Use a browser-based signature tool

Several free online tools let you sign a PDF in your browser without creating an account:

Upload your PDF to the signing tool
Click where you want to add your signature
Draw your signature with a mouse or trackpad, type your name and let the tool style it, or upload a photo of your handwritten signature
Position and resize the signature image on the page
Download the signed PDF

PDF99's sign tool is currently in development — when available it will support all three signature creation methods directly in your browser, with no account required.

Method 2: Use Preview on Mac

If you're on a Mac, Preview has excellent built-in signature support that most people don't know about:

Open your PDF in Preview
Click the Markup toolbar button (the pencil icon) to show the markup tools
Click the signature button (looks like a cursive signature)
Choose "Create Signature" — you can sign on the trackpad or use your iPhone's camera to photograph a signature on paper
Once created, drag the signature to the correct position on the document
Save the PDF

This is completely free, built into every Mac, and produces a proper PDF with your signature embedded — not just a screenshot. The iPhone camera method is particularly good if you want your actual handwritten signature in the document.

Method 3: Use Adobe's free tier

Adobe offers a limited free tier for signing documents through their Acrobat online service. You get a small number of free signings per month before hitting the paywall. For occasional use — signing a lease once, countersigning a contractor agreement — the free tier is sufficient. Create a free Adobe account, upload your PDF, and use their guided signing workflow.

Method 4: Type your name and take a screenshot

This sounds too simple, but for many informal contexts it's perfectly acceptable. Type your name in the signature field, take a screenshot, and embed that as the signature image. Or simply type your name in italics directly into a PDF annotation box. Courts and businesses have accepted typed names as electronic signatures for over 20 years.

What about contracts that need a "proper" signature?

If the other party to a contract specifically requires a qualified electronic signature (QES) or an advanced electronic signature (AES) — which have higher legal standards and require identity verification — you'll need a certified e-signature platform like DocuSign, HelloSign, or similar. These typically charge per document or per month.

For the vast majority of everyday business documents, a standard electronic signature from any of the free methods above is completely sufficient.

Tips for signing professionally

Use black ink when drawing a signature — it photographs most clearly and looks professional on printed documents. Keep the signature consistent with how you sign physical documents — a wildly different digital signature looks suspicious. If you're signing multiple copies of the same document, use the same signature image or drawing to ensure consistency.

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Creating a reusable digital signature

If you sign documents frequently, setting up a reusable signature image saves time. Rather than redrawing your signature every time in a browser tool, create a clean signature image once and save it for repeated use.

The best method: sign your name with a black marker on white paper. Photograph it with your phone in good lighting, ideally natural light from above to avoid shadows. Crop the image tightly around the signature in your phone's photo editor. Email or AirDrop it to yourself. Most browser-based signing tools let you upload an image as your signature, so you can use this photograph directly.

For a cleaner result, scan the signature rather than photographing it. A flatbed scan at 300 DPI produces a sharper image with a more consistent white background. If the background isn't pure white, many image editors have a background removal tool that makes it transparent — a PNG with a transparent background looks the most professional when placed on a document.

Signing documents on iPhone

iOS has signature support built into the Markup tool, which is accessible directly from the Files app and Mail without installing anything. To sign a PDF on iPhone:

The signed PDF is saved in place. Share it directly from Files using the share icon. This method works offline, requires no account, and produces a proper embedded signature rather than a screenshot.

Signing documents on Android

Android doesn't have a native equivalent of iOS Markup, so the best free options are browser-based tools in Chrome or a dedicated app. Adobe Fill and Sign (free, available on Google Play) handles the most common signing scenarios well — upload a PDF, tap to place a signature, save and share. The free tier allows a reasonable number of signings before hitting limits.

For browser-based signing on Android without an app, the process is the same as desktop: open the signing tool in Chrome, upload your PDF, draw or upload your signature, position it, and download the result. This works on any Android device and requires no installation.

Keeping records of signed documents

For any document you sign electronically — especially contracts, agreements, or official correspondence — keep a copy of the signed PDF in a secure location immediately after signing. Cloud storage (iCloud Drive, Google Drive, Dropbox) is appropriate for most documents. For highly sensitive documents, a locally encrypted folder provides more control.

Note the date you signed, who you signed it with, and any reference numbers in a simple log. For business contracts, this log becomes important if there's ever a dispute about whether you signed, when you signed, or what version you signed. A timestamped PDF in your cloud storage combined with a brief note is a lightweight but effective record.

When to use a dedicated e-signature service

Free methods work well for simple single-party signing — signing a document yourself to return to someone. When you need multi-party signing — where two or more people need to sign the same document in sequence, with an audit trail proving each person's identity and timing — a dedicated e-signature service becomes worth the cost.

Services like DocuSign, HelloSign (now Dropbox Sign), and Adobe Sign handle sequential signing workflows where each party gets notified when it's their turn, receives a signed copy at completion, and has their signature timestamped and identity-linked. The resulting signed document includes a certificate of completion that shows who signed, when, from what IP address, and using what authentication method. This level of auditability is valuable for significant contracts even though it comes with a monthly fee.

How to Sign a PDF Online — Free Methods That Actually Work