IconVault's PDF Signature tool lets you sign a PDF without printing, scanning or installing anything. Draw your signature with mouse or touch on the signature pad, or type your name to place it as styled text, then pick the page, position and size with a live placement preview before downloading the signed file.

It is free and runs fully in your browser, so your document is processed locally and never uploaded to any server. The honest note: this adds an electronic signature for informal use (a drawn image or typed name on the page). It is not a certified digital signature and carries no cryptographic proof of identity, so it suits everyday agreements, forms and internal approvals rather than documents that legally require certified signing.