To add a periodic fee type (that will be charged more than once), follow below mentioned steps:
The monthly/quarterly/half yearly fee type is based on your General settings.
Go to Fee Management > Fee Types.
Click on 'Add New Fee Type' button.
Enter Fee Type name.
Enter details as per your requirement.
Select Status as 'Active'.
Note: Periodic = YES means that invoice will be generated more than once (every month) for this fee type.
Note: You can also refer How to add fee type (one-time)