What kind of signature this creates
There are two quite different things people call "signing a PDF".
- A drawn signature places an image of your handwriting on the page. It is the digital equivalent of printing a document, signing it with a pen and scanning it back. This is what this tool does.
- A digital (certificate) signature attaches cryptographic proof of who signed and that the file has not changed since. It requires a certificate issued to you, usually through a bank, a government ID scheme or an e-signature service.
A drawn signature is what most everyday paperwork asks for: rental agreements, freelance contracts, permission slips, HR onboarding forms, delivery confirmations, invoices. Its weight as evidence comes largely from context, such as the email in which you sent it and the fact that both sides acted on the agreement. Documents that by law need a notary, wet ink or a qualified certificate are a different matter, and the organisation requesting them will normally say so.
Making a signature that looks natural
Drawing it
The signature pad accepts a mouse, a trackpad, a stylus or a finger. A finger or stylus on a phone or tablet gives the most natural result; a mouse tends to produce shaky, angular strokes. The pen is a 3-pixel dark ink line with rounded ends.
Use the whole pad. The entire pad area is placed on the document, with the empty parts transparent, so a small signature in one corner of the pad becomes a small signature on the page with a large invisible margin around it. Sign big, edge to edge, and press Clear to start over if the first attempt is not right.
Using a photo
For a signature that matches your paper one exactly, sign on plain white paper with a black or dark blue pen, then photograph it in even daylight without shadows. On upload, light pixels become transparent and darker ones remain as ink, with soft edges kept partly transparent, so the signature sits on the page without a white rectangle around it. The ink colour is kept as photographed.
Two things improve the result noticeably. Crop the photo tightly around the signature first with Crop image, because the whole frame is placed and sized as one unit. And avoid grey or shadowed paper: anything darker than light grey stays visible as a smudge.
Placing and sizing it on the page
Use the page buttons to move to the page that needs signing; the preview shows that page. Click on the preview where the signature should go, and adjust the Size slider, which sets the signature's width from 10% to 60% of the page width. The default of 25% is about 52 mm on an A4 page, close to the length of a typical signature line. For a narrow field such as initials in a margin, 10 to 15% is usually enough.
Before sending, open the downloaded file and check the signature is exactly where it should be, especially on pages with little room around the signature line.
The signature is added as an image to that page only, and the rest of the document, including its text and any filled-in form fields, is left unchanged. If a form has fields to fill in, fill and save them in your PDF reader first, then add the signature here.
Before you send the signed file
- Encrypted documents cannot be opened for signing. Remove the password with Unlock PDF first, if it is your document and you know the password.
- Documents that already carry a certificate signature, for example a contract countersigned through an e-signature service, should not be signed here. Saving a new version breaks the existing signature's integrity check, and the recipient's reader will flag the file as modified.
- Your signature image travels with the file. Anyone who receives the PDF could copy it out, just as they could from a scanned paper document. Send signed documents only to the people who need them.
Everything runs in your browser: the PDF, the drawing and the photo of your signature are never uploaded. Files up to 100 MB are supported.