Even if someone pays you offline, you are able to record the payment within LeagueApps. They will need to be registered for a program with an invoice created before an offline payment can be recorded. Learn how to manually register users here.
Find the invoice that was created when the player registered for the program. You can do this by searching the player's name in the Search Bar.
From the Invoice Actions menu, click "Add Offline Payment".
Enter the amount of the offline payment, the type (Cash, Check, Other) and optionally an offline payment date or note.
Click submit and you're good to go!
Removing an Offline Payment
If you need to remove an offline payment, find the Invoice and click the X next to the offline payment amount. To edit an offline payment, delete the recorded offline payment then submit a new accurate offline payment.