Sign PDF

Purpose

Add electronic signatures to a PDF — handwrite with mouse/touch, upload a transparent PNG, or generate a typed signature in a calligraphy font. Signatures embed as image layers with full control over position, size, opacity, and page selection. Runs locally via Canvas API + pdf-lib; signature and PDF never leave your browser. Free, no watermark, no limits. Perfect for remote contract signing, internal approvals, electronic archive sign-off.

Steps

1. Drag or pick a PDF
2. Pick a signature method: "Handwrite", "Upload image", or "Type with font"
3. Handwrite: draw with mouse or touchscreen; the tool auto-clears the background to produce a transparent PNG
4. Upload: drag a transparent PNG (200×80 pixels recommended)
5. Type: enter your name and pick a calligraphy font
6. Click a thumbnail to select the page to sign
7. Drag the signature to position, resize from the corner handle
8. (Optional) Enable "Apply same position to all pages" for multi-page contracts
9. Confirm and click "Process"
10. Download the signed PDF, suffix "-signed"

FAQ

Will my signature image be uploaded?

No. The canvas-drawn signature, uploaded PNG, or typed signature all stay in browser memory; pdf-lib embeds them directly into the new PDF locally. Your signature image never leaves your device.

Are electronic signatures legally valid?

Under the EU's eIDAS, the US ESIGN Act, China's Electronic Signature Law, and most major legal frameworks, electronic signatures hold legal weight. However, this tool produces a "visual signature" (image layer), not a cryptographic digital signature with PKI certificates. For high-stakes legal contracts, complement with a certificate-based digital signature service plus timestamp.

Can I sign multiple pages at once?

Yes. Enable "Apply same position to all pages" to stamp the same signature at the same coordinates on every page — common for multi-page contracts requiring per-page signing. For different positions per page, sign individually.

Why does my handwritten signature have jagged edges?

The canvas pad produces a clean alpha-channel transparent background, so jaggedness shouldn't happen there. If you uploaded a scanned signature PNG with jagged edges, run it through imgbox's Background Removal tool first to clean the transparency.

Can signatures be altered or removed?

Signatures embed as image layers and can be overwritten or removed in professional editors like Adobe Acrobat Pro. For tamper-resistance, run Encrypt after signing and apply restrictive permissions.

Use cases

• Sign a remote-work contract and email it back
• Quickly approve internal documents with an e-signature
• Add a historical signature to an archival document
• Co-sign a project sign-off across remote stakeholders
• Digitally sign academic integrity statements

Tip

A transparent PNG at 200×80 pixels strikes the best signature balance — too large stands out, too small loses fidelity. After signing a contract, run Encrypt to set "open but no edit" permissions to deter tampering.