This article show three methods that can be used to add audio comments to PDF documents in Adobe Acrobat free and Pro version.

Merge PDF files, two or more, by using the Adobe Acrobat Reader Combine PDF function. Adobe Acrobat Reader DC is the cloud-based version of Adobe Acrobat Pro.

Download free Acrobat Reader DC software, the only PDF viewer that lets you read, search, print, and interact with virtually any type of PDF file.

Like a Kindle, your Kobo e-reader can display a random screensaver image when on standby—you just need to do a bit of quick work.

Adobe offers three of the best free PDF readers we've tested, compatible across Windows, Mac, and mobile: Acrobat Reader DC, Acrobat DC (known as Acrobat Standard DC), and Acrobat Pro DC.