Sign PDF
Draw your signature with a mouse or a finger, place it on any page of a PDF in your browser, and download a signed copy. Your file is never uploaded to a server.
Choose a PDF
One PDF between 1 KB and 50 MB. Select it from your device or drag and drop it here.
How to sign the file
- 01Choose a file
Pick one PDF; the tool checks its type and size and confirms it can be read and rendered, then shows the first page.
- 02Draw and place the signature
Draw your signature on the pad, pick its color and thickness, click the page to set the position, then press “Add signature”. Repeat on any page.
- 03Export and download
pdf-lib rebuilds the file from the original bytes and embeds the signature images at their positions, then the file downloads as signed.pdf.
Is this a certified digital signature?
No. The tool adds a hand-drawn signature image over the page; it is not a cryptographic digital signature and not an electronic signature certificate. The tool does not verify or prove the signer’s identity, creates no credentials, timestamp or audit trail, and does not replace certified or qualified electronic signature services when the receiving party or the law requires them.
What happens to your file?
The file is read and shown entirely in your browser. On export, a new file is built from the original bytes with pdf-lib and the signature images are embedded at each page’s coordinates; neither the file nor the output is uploaded to any server. Re-saving the file this way invalidates any digital signature that was already present, because verification depends on the original bytes staying unchanged.
Before relying on the output
- Open the output and zoom into the signature positions to confirm they are clear and accurate.
- Adjust the signature width so it stays readable without covering important text.
- Keep the original file until you have checked the signed copy.
- Do not add password encryption to the output if you are sending it to a party that must open it directly.
- When an approved or attested signature is required, use a qualified electronic signature service.
Frequently asked questions
Does the resulting signature have legal validity?
The tool places a drawn signature image, which by itself does not create a certified electronic signature and does not prove the signer’s identity. Legal validity depends on the laws of your country and on what the receiving party accepts; if an attested or qualified signature is required, use a specialized service.
Is my file uploaded to a server?
No. The file is read and processed in your browser, and neither its bytes nor the resulting copy are sent to any server. Keeping your files backed up on your device remains your responsibility.
Can several people sign the same file?
Signatures are added one after another within the same browser session; there is no direct sharing between signers and no invitations. If you need a signing order between multiple signers, pass the resulting copy to the next signer to add their signature.
What are the page or file limits?
One PDF between 1 KB and 50 MB, with no theoretical page limit, but very large or many-page files can exhaust browser memory and slow down rendering.
Does file or text quality change?
Pages are copied as-is without re-compression or re-rendering, so text and images keep their original quality. The added signature is a PNG image, so its edges can look soft at very high zoom.
What does the output contain?
The output contains the original pages with the signature images embedded at their positions. No cryptographic signature, certificate or timestamp is added, and the file is downloaded as signed.pdf.