Sign PDF
Add your signature or logo to a PDF and place it exactly where you want — free and entirely in your browser. Your document is never uploaded.
How to sign a PDF
- Add your PDF. Drag and drop the document onto LambiPdf, or click “Choose files.”
- Open the Sign / Stamp tool and upload a signature image (a PNG with a transparent background works best) or a logo.
- Place it and save. Drag on the page to position your signature, then save the signed PDF to your device.
Sign PDFs privately, without uploading
LambiPdf adds your signature using your own browser, so signed contracts and forms never touch a server. It's ideal when you just need to drop a signature or company stamp onto a document quickly, with no account and no watermark. Tip: sign your name on white paper, photograph it, and remove the background to get a clean signature image.
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Sign PDF — FAQ
Is signing a PDF free?
Yes — free, no sign-up, no watermark.
Is my document uploaded?
No. Your PDF and signature image are processed entirely in your browser.
What image works best for a signature?
A PNG with a transparent background gives the cleanest result, but JPG/PNG logos work too.
Is this a legally-binding e-signature?
LambiPdf places a visual signature image; it is not a certified digital e-signature service. For legally-binding signing, use a dedicated e-signature provider.