Sign PDF Free Online — Draw, Type or Upload Your Signature

✍️Sign PDF Free Online — Three Ways to Add Your Signature

Sign PDF is something I do multiple times a week — NDAs, contractor agreements, client approvals, and internal sign-off forms all arrive as PDFs that need a signature before going back. For years I printed, signed by hand, scanned, and re-attached. It was slow and the scanned signatures always looked low quality. This sign PDF tool eliminates that entire workflow — draw directly on the canvas with a mouse or touchscreen, type your name in a handwriting font, or upload a photo of your existing ink signature, then place it exactly where it needs to go on the PDF and download the signed document in seconds.

The signature is embedded directly into the PDF page content using pdf-lib — rendered as a transparent PNG image placed at the exact coordinates you specify. Your file never leaves your browser. According to Adobe's official PDF signing documentation, there are two distinct types of PDF signatures: visual electronic signatures (appearance-based, which this tool creates) and cryptographic digital signatures (certificate-based, using PKI). This tool creates visual electronic signatures — the kind accepted for the vast majority of business and personal documents.

The sign PDF tool gives you precise placement control: choose the page, set the X and Y position in millimetres from the bottom-left, and set the width. This means you can place the signature exactly on the signature line of a form or contract — not just somewhere on the page. As the ISO PDF standard defines, images embedded in PDF page content streams are part of the permanent page rendering — the signature appears identically in every PDF viewer with no plugins required.

📋How to Sign PDF — Step by Step

👥When You Need to Sign PDF Online

• Business contracts and NDAs: The most common sign PDF use case is business agreements. Contracts, NDAs, service agreements, and supplier forms all arrive as PDFs that need your signature before being returned. This sign PDF tool lets you sign and return documents in under 60 seconds — without printing, scanning, or installing any software.
• Rental and property agreements: Lease agreements, rental applications, and property management forms are routinely sent as PDFs for electronic signing. Using this tool to sign PDF documents means you can complete paperwork immediately from any device — including a phone or tablet using the touch-screen signature canvas.
• Employment and HR documents: Offer letters, onboarding forms, benefits enrollment documents, and employee policy acknowledgements all require signatures. HR departments increasingly accept electronically signed PDFs. Sign PDF documents as soon as they arrive and return them the same day rather than waiting for access to a printer.
• Client approval documents: Agencies, consultants, and freelancers frequently need client signatures on project briefs, scope documents, and approval forms. The sign PDF tool lets clients sign a PDF document you send them from any device, without needing a pdf editor or account. See G2's e-signature tool comparison for how different electronic signing approaches compare across industries.
• Personal and government forms: Tax forms, insurance documents, loan applications, and government forms are increasingly distributed as PDFs. Being able to sign PDF documents electronically means you can submit forms online without a physical visit or a printer — a practical time-saving for routine paperwork.

🔬How This Sign PDF Tool Works

• Draw mode uses the HTML5 Canvas API: When you draw in the signature pad, mouse/touch events are captured and rendered onto an HTML5 Canvas element in real time using requestAnimationFrame for smooth strokes. Each completed stroke is stored in a history array for undo functionality. The canvas is exported as a transparent PNG using canvas.toDataURL('image/png').
• Type mode renders text to a canvas: When you type your name and choose a font, the text is rendered onto an offscreen canvas using the selected Google Font (Dancing Script, Caveat, or Pacifico) at a large size. The canvas is then exported as a PNG with a transparent background, preserving the handwriting appearance when overlaid on the PDF page.
• Image mode reads the uploaded file via FileReader: When you upload a signature PNG or JPG, FileReader reads it as a Data URL. The image is displayed for preview and the raw ArrayBuffer is passed to pdf-lib's embedPng() or embedJpg() for embedding in the PDF.
• pdf-lib draws the signature image onto the PDF page: After selecting a signature and placement settings, pdf-lib loads the PDF via FileReader, embeds the PNG signature image, and calls page.drawImage() at the exact coordinates converted from millimetres to PDF points (1mm = 2.835pt). The image is placed with a transparent background so only the signature strokes appear over the existing page content.

🏆Sign PDF Tools Compared

💡Tips for a Great PDF Signature

• Use a tablet stylus or touchscreen for the most natural drawn signature: Drawing a signature with a mouse often produces a slightly mechanical look. If you have a touchscreen device — phone, tablet, or laptop — the draw mode canvas supports touch events natively, producing a much more natural looking sign PDF result that closely matches a real handwritten signature.
• Upload a high-resolution PNG with a transparent background: The cleanest image watermark sign PDF results come from a PNG file with a transparent background. Take a photo of your signature on white paper, crop it tightly, and use a background-removal tool to make the background transparent before saving as PNG. The signature then sits cleanly over any PDF page content without a visible white box around it.
• For typed signatures, Dancing Script looks most professional: Among the three font options in this sign PDF tool, Dancing Script produces the most formal and document-appropriate handwriting style. Caveat works well for a more casual look, and Pacifico is distinctive for creative or personal documents. All three are free Google Fonts with consistent rendering.
• Find the correct Y position by measuring from the bottom: PDF coordinates measure Y from the bottom of the page — not the top. A standard A4 page is 297mm tall. If the signature line is 30mm from the top of the page, set Y to 297 − 30 = 267mm. For a signature at the bottom of the page (e.g. 20mm from the bottom), set Y = 20mm. This is the most common source of placement mistakes when you sign PDF documents with coordinate-based tools.

❓Frequently Asked Questions

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