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Sign PDF
FreePlace a signature image on page 1 — click to position, slider for size. Visual signature, not cryptographic e-sign (see FAQ).
What you'll get: a PDF with your signature image placed at a clicked position on page 1 — adjustable size, lossless overlay. Visual signature only, not a cryptographic e-sign (see FAQ). For another use, try Image Watermark.
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Stays in your browser
Free tools run fully on-device — nothing is uploaded to a server.
No watermarks
Clean output, no branding, no daily limits.
Free forever
No signup required. Seriously.
Why people sign PDFs visually
Most signature requests aren’t legally binding contracts — they’re forms that need a recognizable mark, expense reports that need approval, internal docs routed for sign-off. A pasted-in signature image solves the common case in seconds.
Internal approval
Stamp your signature on expense reports, time-off requests, or routine internal forms before sending up the chain.
Filling out forms
Tax forms, school enrollment, gym waivers — fields that ask for a signature but don’t require cryptographic binding.
Routine paperwork
Vendor onboarding forms, expense pre-approvals, NDAs that don’t need DocuSign-grade audit trail.
Cover letters
Add a signature to job application cover letters when the employer expects to see one.
Academic submissions
Permission slips, recommendation letter sign-offs, grant agreement annexes.
Form sign-offs
Liability waivers, photo releases, treatment consent — internal-process forms that move the document through the workflow.
How Sign PDF works
Three steps, no signup, no uploads.
- STEP 1Drop your PDFUp to 100 MB. PDFium renders page 1 at 1.5× as the editor canvas.
- STEP 2Pick a signature imagePNG (with transparency works best — drops cleanly onto the form line) or JPG, up to 10 MB. The image preview appears in the config panel.
- STEP 3Click + sizeClick anywhere on the page to place the signature. Drag the size slider (5–60% of page width) until it fits the signature line. Click elsewhere to move it.
- STEP 4Apply & downloadWe embed the image and drawImage at the chosen position via pdf-lib. Lossless overlay; original page content untouched.
What makes pdfcraft ai different
- Same engine Chrome usesPDFium is Google's PDF engine — the one that powers Chrome's built-in PDF viewer. We compile it to WebAssembly so it runs in your browser at near-native speed.
- 100% local processingMost free PDF tools upload your file to a server, process it, and stream the result back. We don't. Your file lives in your browser tab and never touches our infrastructure. Verifiable in your browser's Network panel.
- No watermark, no signup, no daily limitConvert 1 PDF or 1,000. We don't gate on volume because there's nothing to gate on — the engine runs on your machine.
- Honest about limitationsWhen something the tool can't do (encrypted PDFs, cross-reference streams), we tell you clearly instead of failing silently. Same for partial results: sampled vs exact, embedded vs not.
- Open standards, free enginesPDFium is BSD/Apache licensed (free for any use). We don't pay vendor license fees and pass that savings on to you (and to ourselves) as a free, ad-supported tool with no upgrade-to-pro pressure.
Frequently asked questions
Is this a real (cryptographic) e-signature?
No. This places a signature IMAGE on the page — there’s no signing certificate, no integrity hash, no signer identity. Anyone with the PDF can add or remove signatures. For binding contracts (real estate, employment, NDAs of consequence), use DocuSign, Adobe Sign, HelloSign, or another service that produces a signed PDF with an audit trail.
When IS this enough?
When the recipient just needs to see a signature mark — internal expense forms, school permission slips, gym waivers, routine paperwork. The legal threshold is usually ‘reasonable evidence the signer agreed.’ A pasted signature image clears that bar for most informal contexts. Talk to a lawyer for specific cases.
Why does my signature look pixelated?
Either the source image is small (try a higher-res scan of your signature) or the size slider is set too high (a 200×80 px image stretched to 50% of an 8.5" page = visible pixelation). For best results, scan at 300 DPI and use 15-25% size on the slider.
Will the signature show on every page?
v1 = page 1 only. Multi-page signing (e.g. initials on every page + final signature on page N) needs page navigation in the editor — a v2 enhancement.
Can I add multiple signature images?
Not in v1 — one click position, one image. To add date / initials / multi-line signature blocks alongside the image, run Add Text to PDF afterwards on the signed output.
Is anything uploaded?
No. PDFium renders the preview locally; pdf-lib applies the image locally. Both your PDF and your signature image stay in your browser — important for sensitive forms.
Do PNG transparency channels work?
Yes. Transparent PNGs let the form line / page content show through where the image is transparent. JPEGs don’t support transparency, so they always render as opaque rectangles — use PNG for signatures whenever possible.
Need to add a date or printed name?
Add Text to PDF places typed text at a click position — the natural pairing with a signature image.
Try Add Text to PDFRelated PDF tools
Other tools in the Edit category — built on the same private, in-browser pipeline.
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PDF OverlayFree
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Batch Process PDFsFree
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Rotate PDFFree
Rotate selected pages by 90°/180°/270°. Lossless via pdf-lib's /Rotate adjustment — runs in milliseconds.
Use cases for this tool
Step-by-step workflows that put this tool to work.