Monthly: Includes all payrun ran for the same month. It can only be used once in a month.
Fortnightly: Includes payruns that are paid every fortnight (2 weeks). It can only be used once in each fortnight.
Adhoc: Includes additional payruns for staff that was done on top of the normal payrun. It can used multiple times, need to approve the first Adhoc run and do another Adhoc run.
How to process a payrun?