PDF Sign
Draw, type, or upload a signature — then click to place it on any page of your PDF.
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Draw or type a signature, then drop it onto a PDF at the exact spot, size, and page you need. Skip the print-sign-scan-email loop for documents emailed in for a quick signature, and work around forms whose creator forgot to add real signature fields. The signature image, its position, and the source PDF stay in your browser's memory throughout — none of it travels to a server, which is the point of signing a document about yourself in the first place.
Next steps
Organize pages
RecommendedDrag pages to reorder, rotate individual pages, and delete pages — then export.
Merge PDFs
RecommendedMerge multiple PDFs into a single file — drag, drop, done.
Compress PDF
Compress PDFs to a fraction of their size — perfect for email.
Protect PDF
Lock sensitive PDFs with a password or remove existing protection.
Runs right inside your browser tab. No uploads. Your files stay private.
How to Sign a PDF in the Browser — Drawing, Typing, or Uploading
PDF Sign places a visible signature image into a PDF using two libraries: pdfjs-dist (Mozilla's PDF.js) renders each page onto a canvas so you have an accurate preview to position the signature on, and pdf-lib embeds the resulting signature as a PNG image into the page's content stream when you export. Both libraries run on your machine and only your machine, so the document never leaves your device.
Three input methods are supported. Draw uses an HTML canvas with pointer event tracking — pen input on iPad and Surface devices is captured as smooth strokes via pointer events, and the result is exported as a transparent PNG. Type renders your name in an italic display font onto an offscreen canvas so it looks closer to handwritten signature than a system font. Upload accepts PNG or JPG images of a scanned physical signature; PNGs with a transparent background look best because there is no white rectangle around the strokes.
Click on the page preview to drop a signature. Each placement stores normalized coordinates (relative to the page's media box) so positions remain accurate at any zoom level. Drag a placed signature to reposition, and use the size slider to scale. Multiple placements per page are supported, including initials on every page in a long contract.
On export, pdf-lib embeds the signature PNG using the embedPng method, then draws it on each placed page at the stored coordinates. The output is a standards-compliant PDF that opens identically in Adobe Acrobat, browser PDF viewers, macOS Preview, and mobile readers.
An important distinction: this is a visible electronic signature, not a cryptographic digital signature. Electronic signatures are legally binding in most jurisdictions under laws like the US ESIGN Act and the EU eIDAS regulation when they show clear intent to sign. Cryptographic digital signatures (PKCS #7 / CAdES, the kind that show a green checkmark in Acrobat) require certificates, timestamping authorities, and PDF/A-compliant signing — a workflow that browsers cannot complete without server-side certificate handling.
Encrypted PDFs cannot be parsed by pdf-lib until they are unlocked — use the PDF Password tool first. PDFs with existing digital signatures will see those signatures invalidated by adding a new image; this is part of the PDF signing standard.
Practical limits: PDFs up to ~200 pages and ~100 MB are comfortable. Very long documents take longer to open because pdfjs-dist renders every page to a thumbnail up front so you can navigate and place signatures on any page. For initialing every page of a 300-page document, splitting into halves with PDF Splitter and signing each separately is faster.
Common Use Cases
01
Sign contracts without printing
Add a drawn or typed signature to a PDF and email it back without ever touching a printer or scanner.
02
Initial every page of a contract
Navigate page-by-page and stamp initials on each, with a placements summary showing how many signatures are on every page.
03
Sign on tablet or phone
Pen input on iPad, Surface, and Android stylus devices is captured through pointer events for a smooth, natural-looking signature.
04
Embed a scanned ink signature
Upload a transparent PNG of your real signature and place it where you'd normally sign on paper, sized to fit the signature line.
Frequently Asked Questions
Yes for most everyday use. Electronic signatures are recognized as binding under laws like the US ESIGN Act and EU eIDAS when they clearly show intent to sign. For high-value or regulated transactions (real estate closings, notarized documents) a platform with audit trails and identity verification is advisable.
This tool produces a visible electronic signature — an image embedded into the PDF. A digital signature uses PKCS #7 cryptography, a personal certificate, and a timestamp authority to prove identity and integrity. Browsers cannot create those without server-side certificate handling.
No. PDF.js renders pages and pdf-lib embeds the signature, both running inside your browser. The document stays in tab memory and is never transmitted.
Not directly — pdf-lib refuses to parse encrypted streams. Remove the password using the PDF Password tool first, sign, then re-encrypt if needed.
PNG and JPG. For best results use a PNG with a transparent background so the signature appears cleanly on the document without a white rectangle. Aim for at least 600×200 pixels at 300 DPI for sharp edges when zoomed.
Yes. Navigate between pages using the arrows and click to place. The placements panel summarizes how many signatures are on each page before export, and any placement can be deleted or repositioned individually.
Drawn and uploaded signatures are stored as PNGs at the resolution they were captured. For 300 DPI print quality, draw on a high-DPI device or upload a scanned signature at 600×200 pixels or larger. Typed signatures are rendered to a canvas as a PNG, so keep them at a moderate size on the page for the sharpest result.
Yes. Any modification to a digitally signed PDF — including adding a visible signature image — invalidates the existing cryptographic signatures. This is part of the PDF signing standard.
Not in this tool. Browser-based certificate signing is impractical because it would require uploading the certificate or installing native code. Desktop Acrobat or qpdf with a signing plugin remain the standard for cryptographic signatures.
There is no hard cap. PDFs up to about 100 MB and 200 pages are comfortable on a modern laptop. Very long documents slow down because every page must be rendered for thumbnail navigation.
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