Using iStudiez Pro on iOS or Android device tap a checkbox left to assignment's/exam's name to mark it as completed and enter your grade. 

On Mac and Windows - check a checkbox left to assignment's name to mark it as completed.
Do the following to complete your exam:
- from the Overview: 1) double-click your exam > click "Mark as Completed" button, or 2) right mouse click on your exam entry > Mark Exam As Completed


- from the Planner: go to the Planner > Semester > Course > Schedule > open exam entry to edit the details > check a checkbox left to exam's name to mark it as completed and enter your grade.