Choose appropriate application or application part in the main menu and click "Permission types". Click "New Permission Type" and fill in permission type details:
Name - permission type name.
Description - permission type description.
Alias - permission type alias. It is used for hard-coding names of permission types within your application code. It shouldn't be changed later.
Copy to Application Parts - if checked, the permission type will be copied to all underlying application parts, as well as to those that will be created later.