How to Sign a PDF Online

Sign a PDF step by step

1. Open the document in the SmartPDF editor and go to the page with the signature line.
2. Choose Sign in the toolbar (shortcut S). A drawing pad opens.
3. Draw your signature with your mouse, trackpad, finger or stylus. Choose black or blue ink. Press Clear to start over.
4. Optional: tick Reuse this signature until I close the document if you need to sign several pages.
5. Press Place signature. It appears in the middle of the current page, selected.
6. Drag it onto the signature line and use a corner handle to resize it. The proportions are kept so it never looks stretched.
7. Add the date with the Text tool if needed, then press Download Edited PDF.

Tips for a clean signature

• Sign bigger than you need. Draw across most of the pad, then shrink the signature on the page. Small drawings look shaky when enlarged.
• Use a touchscreen or stylus if you can. A finger on a phone usually gives a more natural result than a mouse.
• Zoom in before placing it so it sits neatly on the line without overlapping printed text.

Drawn signatures vs. digital signatures

There are two very different things people call “signing a PDF”:

• A drawn (electronic) signature is an image of your handwriting placed on the page. That is what SmartPDF creates. Many everyday documents — permission slips, delivery notes, internal approvals, many contracts — accept this kind of signature.
• A certificate-based digital signature uses cryptography and an identity certificate to prove who signed and that the file hasn’t changed since. Some legal, government and financial processes require it. SmartPDF does not create this kind of signature.

Requirements differ by country and by organization. If you aren’t sure which kind is needed, ask whoever requested the signature. This guide isn’t legal advice.

Privacy of your signature

Your signature is drawn and stored only in your browser’s memory while the document is open. It isn’t uploaded or saved to your device by SmartPDF, and it’s cleared when you close the document or the tab. The only copy that remains is inside the PDF you download — so share that file with care.

Signing a PDF that’s already digitally signed

If someone has already applied a certificate-based signature, any change — including adding your drawn signature — will invalidate theirs. SmartPDF warns you when it detects this. In that case, use the signing workflow the sender intended.