Signing places your signature onto the page: draw it with a mouse or finger, type your name in a handwriting font, or upload a photo or scan of a signature you already have. Position it where it belongs, add a date or initials if the document needs them, and download the signed PDF. This produces an electronic signature — a visible mark that, together with the surrounding evidence of who sent what and when, is legally sufficient for most everyday agreements in most jurisdictions. It is not a cryptographic digital signature, which binds an identity certificate to the document and can prove mathematically that nothing changed afterwards. Knowing which one a document needs matters. Everything happens in your browser: the document and the signature image are never uploaded, which is worth something given what people sign.
Electronic signature or digital signature
An electronic signature is the broad legal category: a mark applied with intent to sign. Under frameworks like the US ESIGN Act and the EU's eIDAS, a typed name, a drawn squiggle or a clicked checkbox can all qualify, and the evidence that matters is usually contextual — the email trail, the timestamps, the parties' conduct.
A digital signature is a specific technology: a certificate issued to an identity, used to sign the document's hash, so any later change invalidates the signature. Some documents demand it — regulated filings, certain government submissions, qualified signatures under eIDAS. This tool does not produce one, and no tool can without an issued certificate.
Which method looks right
Drawing is the most natural on a touchscreen and the least so with a mouse, where signatures tend toward an unconvincing wobble. Typing in a handwriting font is consistent and legible, and reads as what it is: a typed signature, which is perfectly acceptable in most contexts.
Uploading a scan gives the closest match to a wet signature. Photograph a signature on white paper in good light, and crop tightly. A PNG with a transparent background sits cleanly over the page; a JPEG brings its white rectangle with it, which shows against any shading or a line it is meant to sit on.
Before you send it back
Check the signature is on the right page and not overlapping a line or box it should sit above. Add the date if the document has a date field — an unsigned date field is one of the more common reasons a signed document comes back.
Once saved, the signature is page content and cannot be repositioned, so keep the unsigned original if there is any chance of another round. And if a counterparty asks for a digitally signed document with a verifiable certificate, this is the point to say so rather than sending an image and hoping.