To add, edit, or delete payment categories, Click on Settings > Categories, 

From here you can choose to "Add Payment Category" or under "Actions" select the Edit button on the item you wish to edit.

Fill out the information needed and Click "Add New Category" or "Save" if you are editing an existing category. 

Categories are used to segment payment types. 

For example, you can create categories such as "Parking," "Maintenance," or "Late Fee."