Password Protect a PDF

Email is not a private channel. A message can be forwarded, a shared drive can be opened by the wrong colleague, a laptop can be left on a train. Whenever a document holds a salary figure, a medical result, a signed contract, a passport scan or a client's personal data, adding a password before it leaves your hands is the simplest safeguard there is — the file becomes unreadable to anyone who does not have the key.

Upload your PDF, choose a password and confirm it, and the document is encrypted. From then on every PDF reader — Acrobat, a browser, a phone, an e-reader — will ask for the password before showing a single page. The protection travels with the file, so it stays in force after the document is emailed, copied to a memory stick or uploaded to a shared folder.

Two practical rules make this actually secure. Choose a password worth having: long, unusual, not the recipient's date of birth or the name of the file. And send it separately — through a phone call, a message or a different channel — because a password written in the same email as the attachment protects nothing at all. Keep an unencrypted copy for yourself, since a lost password cannot be recovered. The tool is free, adds no watermark, and deletes your file from the server after processing.