Add Signature to PDF

Two different things called a signature

An electronic signature is an image of a signature placed on the page. It is what this tool produces, and it is what most people mean and most situations require. A digital signature is a cryptographic operation binding a certificate to the document's exact bytes, which proves both who signed and that nothing changed afterwards. The first is a picture; the second is verifiable mathematics. They are routinely confused and are not interchangeable where the distinction matters.

Is a drawn signature legally binding?

In most jurisdictions, generally yes. The EU's eIDAS regulation, the US ESIGN Act and UCETA, and equivalent frameworks elsewhere recognise electronic signatures for most commercial agreements. What differs is the evidential weight if a signature is disputed, and certain categories are commonly excluded, typically wills, some property transfers, and certain family law documents. If a transaction is high value or the counterparty is unknown, a qualified digital signature with an identity-verified certificate carries far more weight. This is general information, not legal advice.

Placement and appearance

Signatures are drawn onto the page as an image, so size and position are fixed once applied. A signature that looks right on screen can print oversized if the page is scaled, so check against the actual printed dimensions. A drawn signature captured with a mouse looks noticeably unlike a real one; a trackpad or touchscreen produces a much more natural stroke, and a photograph of a genuine signature on white paper, background removed, is the most convincing.

Flattening

Applying the signature merges it into the page content so it cannot be dragged away or deleted by a recipient. An unflattened annotation can be moved or removed in any PDF editor, which undermines the point.

Never upload a document to sign it

The documents people sign are contracts, agreements and financial paperwork. Uploading one to a remote service places a copy of a legally significant document on a third-party server. This tool reads and writes the file entirely in your browser.