If you are unable to add text or comments, check the following: Security Settings
Security was a major focus for this release. Building on the Protected Mode introduced in Reader X, Adobe enhanced it in Reader XI to include data theft prevention capabilities. A new Protected View was added, which implemented a separate desktop and winstation for the UI, providing an additional layer of defense against malicious code. adobe reader xi version 11.0.23
Option 1: Upgrade to Adobe Acrobat Reader (Continuous Release) If you are unable to add text or
Images inserted in emails were being converted to garbled text when converted to PDF. The update fixed this conversion error. Option 1: Upgrade to Adobe Acrobat Reader (Continuous
A highly secure, fast PDF viewer that offers extensive enterprise deployment customization, similar to Adobe Reader XI, but with modern security patches. Sumatra PDF