This article will show you how to enter a reason for a student's absence in the Attendance iOS app, which is currently in beta. If you would like to join the beta, please click here for instructions.
When you open the Attendance app, you'll see a list of your classes for the day.
Tap on the class you wish to take roll. Then all you have to do is tap on a student and you will mark them as present/absent - it's that easy!