How to Sign a PDF Document

The old way to sign a contract involved printing it out, signing it by hand, scanning it, and emailing it back. It worked, but it was slow, wasteful, and required a printer. Today, you can sign a PDF directly — digitally — and send it back in minutes, from anywhere. And for the vast majority of everyday agreements, this carries exactly the same legal weight as a handwritten signature.

This guide explains the difference between electronic signatures and digital signatures (a distinction that trips up a lot of people), covers the three main ways to sign a PDF, and walks through each major platform’s signing workflow.

Electronic Signature vs. Digital Signature: What’s the Difference?

These terms are often used interchangeably, but they mean fundamentally different things:

Electronic Signature

Any electronic indication of intent to agree — broadly defined. This includes:

• A drawn signature image on a PDF
• An uploaded image of your handwritten signature
• Your typed name in a signature font
• Checking a checkbox to “agree to terms”

Electronic signatures are legally valid in most jurisdictions (including the US under the ESIGN Act, EU under eIDAS, and many other countries) for most commercial agreements. However, they don’t inherently verify who signed or whether the document was modified after signing.

Digital Signature

A more rigorous, technology-specific type of electronic signature that uses Public Key Infrastructure (PKI). The signer uses a digital certificate issued by a trusted Certificate Authority (CA). The signing process creates a cryptographic “fingerprint” that is embedded in the document.

• Can verify the signer’s identity
• Can detect if the document was tampered with after signing
• Required for some high-stakes contexts (government documents, certain legal filings)
• Requires a digital certificate from a CA

Bottom line: for everyday contracts, consent forms, and business agreements, an electronic signature is sufficient. Digital signatures are for situations where identity verification and tamper-evidence are legally required.

Three Ways to Create an Electronic Signature

• Draw your signature: Use a mouse, trackpad, or touchscreen to draw your signature directly on the document. Feels most authentic but is hard to make look natural with a mouse.
• Use an image: Sign on white paper, photograph or scan it, clean up the background, and insert it as a PNG image. Best-looking result that most closely resembles your real signature.
• Type your name: Type your name and the tool renders it in a cursive/script font. Fastest method, though some people feel it looks less “official.”

Method 1: Online Tools

Best for occasional signing without installing any software.

1. Open our online PDF signing tool (link at the end of this article).
2. Upload the PDF that needs to be signed.
3. Navigate to the signature field or the area where your signature belongs.
4. Choose your signing method:
   • Draw: Draw your signature with a mouse or trackpad in the signature box
   • Upload image: Upload an image of your handwritten signature (the tool usually removes the white background automatically)
   • Type: Enter your name and choose a signature font style
5. Drag the signature to the correct position on the document and resize as needed.
6. Use the text tool to add a date or other required fields if needed.
7. When everything looks correct, click “Finish” and download the signed PDF.

Method 2: Mac Preview (Best Free Option)

Preview has a powerful built-in signature feature that most Mac users have never discovered.

1. Open the PDF in Preview.
2. Click the Markup toolbar icon (the pencil icon) or go to View → Show Markup Toolbar.
3. Click the Signature button (it looks like a cursive script).
4. Choose your capture method:
   • Trackpad: Sign directly on your trackpad with your finger, then press any key.
   • Camera: Sign on white paper and hold it up to your Mac camera — Preview automatically detects and removes the background.
   • iPhone/iPad: If you have Continuity set up, sign on your iPhone’s touchscreen and the Mac receives it in real time.
5. Preview saves your signature for future use.
6. Click your saved signature; it appears on the document. Drag it to the correct position and resize.
7. Save with Command + S, or export as PDF.

Method 3: Adobe Acrobat (Most Feature-Rich)

Acrobat Reader (free) includes signing capabilities. Acrobat Pro adds advanced workflow features.

1. Open the PDF in Acrobat (Reader or Pro).
2. Click Fill & Sign in the right tool panel, or go to Tools → Fill & Sign.
3. Click “Sign Yourself” → “Add Signature.”
4. Choose your method: Type, Draw, or upload an Image.
5. Click Apply, then click the location on the document where the signature should go.
6. Resize and reposition as needed.
7. Use the text tool for date fields or other required information.
8. Save the document.

Method 4: Windows

• Adobe Acrobat Reader (free): The process above works identically in the free Reader version — no Pro subscription needed for basic signing.
• Microsoft Edge (built-in to Windows 11): Open the PDF in Edge, click the Draw tool icon in the toolbar, and draw your signature. When done, print to PDF to save a copy with the signature embedded.

Method 5: Professional E-Signature Services

For multi-party signing workflows, audit trails, or legally certified signatures:

• DocuSign: The most widely recognized e-signature platform globally. Strong legal standing, audit trail, multi-party workflows.
• Adobe Sign: Deeply integrated with Acrobat, excellent for enterprise workflows.
• HelloSign / SignNow: More affordable options with solid features for small business use.

Legal Validity of Electronic Signatures

In the United States, the ESIGN Act (2000) and UETA give electronic signatures the same legal weight as handwritten signatures for most commercial and consumer transactions. The EU’s eIDAS regulation establishes three tiers of e-signatures: simple, advanced, and qualified. The UK, Australia, Canada, and most other developed economies have comparable laws.

For day-to-day business contracts, service agreements, and consent forms, an electronic signature is legally binding and widely accepted. Exceptions — where special rules may apply — include wills, certain real estate transactions, and specific government documents. When in doubt about a high-stakes document, consult a legal professional.

Do it in your browser — the file never leaves your device: PDF Tools