Similar to a feature that first made its way to the Mail app under OS X Yosemite, iOS 9 now includes Markup, a tool that lets you annotate email attachments, including image files as well as PDFs, effectively turning the Mail app into a more powerful one with a growing focus on productivity.
Just like its OS X counterpart, Markup for iOS 9 allows you to sketch, zoom, add text, and sign documents on the go. Absent from the list of annotations is the Shape button, which lets you easily insert squares, circles, etc.
Markup for iOS 9 works for both incoming or outgoing attachments, meaning that you can annotate either the attachments you receive, or those that you send. This seems to actually go hand in hand with another new iOS 9 feature that lets you attach documents from iCloud Drive. Read More