Sign PDF Online Free

Adding an electronic signature to a PDF drops your handwritten signature — drawn with a finger or trackpad, or uploaded as an image — onto specific positions in the document. This is the standard workflow for signing contracts, forms, agreements, and other legal or administrative documents that require your identity on paper (or its digital equivalent). The tool distinguishes between drawing a fresh signature (using a canvas signature pad) and uploading an existing signature image. Both approaches produce identical results in the output PDF: a PNG image overlaid on the page at the position you specify. Everything runs in your browser. The signature never leaves your device — no server ever sees it. The final PDF is a standard file with the signature baked into the page content, viewable in any PDF reader.

Last reviewed: July 2026

What is this?

Electronic signatures (what this tool creates) are legally recognized handwritten marks captured digitally. In the US, they are backed by the ESIGN Act of 2000; in the EU, by eIDAS regulation. They differ from digital signatures, which use cryptographic keys to certify document integrity and signer identity — those require a certificate authority and specialized software. Most business documents (contracts, NDAs, employment forms) are validly signed with electronic signatures alone. Digital signatures are needed only for specific high-stakes contexts like notarized documents or government filings requiring cryptographic verification.

How to use this tool

1. 1Choose the PDF to sign. The tool loads the document and shows a page-by-page preview.
2. 2Draw your signature with your mouse, trackpad, or finger on the signature pad. Alternatively, upload an existing signature image (PNG or JPEG) — a transparent PNG works best for a professional look.
3. 3Drag the signature to the position on the page where it should appear. Resize by dragging the corner handle. Add the signature to multiple pages if the document requires signatures throughout.
4. 4Click Save. The tool embeds the signature into the PDF as a page overlay and produces a downloadable file. Test the output — the signature should be permanently visible on the page, indistinguishable from a signature written on paper and scanned.

Tips & best practices

• For a professional look, upload a signature image with a transparent background instead of drawing on the canvas. Save your signature as a PNG on a separate device and reuse it.
• Draw your signature slowly and firmly. Small trembles from mouse control show up in the output — the canvas smooths but does not correct.
• Signatures are stored as PNG images in the PDF, not as vector paths. Very large signatures may add 100-500KB to file size.
• This tool creates electronic signatures, not digital (cryptographic) signatures. For notarized documents requiring cryptographic verification, use a specialized service like DocuSign, Adobe Sign, or a certificate-based signing tool.
• Some jurisdictions require timestamped signatures or signer identity verification for certain document types. Check local requirements — a hand-drawn signature is enough for most business contracts but not for property deeds or wills in many places.