Need to edit a PDF document but don’t want to pay for the more expensive Adobe editors? You can add text to and sign a PDF with just the free Reader program.

To password protect a PDF in Adobe Acrobat Reader, you'll need the paid Pro version, which starts at $14.99 a month.

Sending important documents? Learn how to password protect PDFs for extra security using easy steps with Adobe Acrobat and free online tools.

How to Lock PDF Files. In the digital age, business documents can be easily leaked or altered. Adobe's portable document format allows strong encryption using a password, certificate or a rights ...

With Adobe Reader, signing your documents electronically is simple. Here's how to sign a PDF on Windows using Adobe Reader.

How to encrypt and password-protect ZIP files the right way This tip was originally published on IDG Answers, a reader-powered help desk for answering tech questions.