Sign PDF

Sign PDF puts your signature on a PDF in your browser: draw it with a mouse, finger or stylus, type your name in a handwriting-style font, or upload a photo or scan of your signature, then place it on any page, add the date or your printed name, and download the signed PDF. It is for the everyday paperwork that asks you to "sign and return" — a lease, a consent form, an invoice approval, a school letter — when you do not want to print, sign and scan.

Be clear about what kind of signature this makes. It is a visual electronic signature: a picture of your signature (vector pen strokes when you draw it, an image when you type or upload it) drawn onto the page. It is not a certificate-based digital signature — there is no certificate, no cryptographic seal and no PAdES signature, so the PDF does not prove who signed it or detect later changes. In the EU, the eIDAS Regulation (EU) No 910/2014 defines an electronic signature as data in electronic form attached to other data and used by the signatory to sign, and says it shall not be denied legal effect solely because it is electronic; only a qualified electronic signature, made with a qualified certificate and signature-creation device, has the equivalent legal effect of a handwritten signature. In the US, the ESIGN Act says a signature or contract may not be denied legal effect solely because it is electronic, but it excludes some documents, including wills, family-law matters and court documents. Whether a picture of your signature is enough depends on the document and the jurisdiction; when a contract, a public authority or your bank asks for an advanced or qualified signature, use a trust-service provider instead. This page is not legal advice.

How it works: pdf.js shows the page you are on, and your signature is kept in page points so it lands exactly where you put it, on rotated pages too. A drawn signature is smoothed into curves and saved as vector lines, so it stays sharp at any zoom. A typed signature uses your device's own cursive, serif-italic or sans-serif font and is saved as the image you see, so it looks the same everywhere. An uploaded picture is scaled to at most 1,600 px on its longest side and, if you leave "Remove white background" on, pixels lighter than the threshold become transparent so the paper does not show as a box. Saving draws everything on top of the original pages with pdf-lib — the rest of the PDF, including links and form fields, is kept — and downloads <name>-signed.pdf.

Password-protected PDFs are refused. If the PDF already carries a certificate-based digital signature, you are warned that saving will make it stop validating. Limits: one PDF up to 200 MB and a signature image up to 15 MB.

Nothing is uploaded: the PDF and your signature stay in your browser tab. You can verify it in the developer tools' Network tab — no request carries your file or your signature (the page loads its own scripts, fonts and analytics, which never include them).

1. The PDF is checked for the PDF signature and opened with pdf-lib; encrypted files are refused and each page's visible area and rotation are read. pdf.js renders only the current page. 2. Drawn signature: pointer positions (mouse, touch or pen) are recorded on a 600 × 200 pad, points closer than 1 unit are dropped, and each stroke is smoothed into quadratic Bézier curves through the midpoints of consecutive points. 3. Typed signature: your name is drawn at 120 px in the chosen generic font family on a canvas cropped to the text and saved as a transparent PNG. Uploaded signature: scaled to at most 1,600 px on the longest side; with background removal on, a pixel whose luminance (0.2126 R + 0.7152 G + 0.0722 B) is at or above the threshold (default 200) becomes transparent, and pixels up to 40 below it fade proportionally. The Strength slider sets the threshold as 255 − strength, so a higher strength removes more. 4. A new signature is centred on the page at 30% of the page width (at most 220 pt, about 7.8 cm) and at most a quarter of the page height; you then move and resize it. The date line is your device's local date in the format you pick. 5. On save, pdf-lib draws each item over the original page content — strokes as vector paths, images embedded once — and saves <name>-signed.pdf.