Financial Settings / General Settings / e-Payments / Basic Settings / Allowed Payment Method
Requires you to have activated the “Enable online payments “setting.
When users pay online, they can choose a payment method. In this setting you can set the allowed payment methods.
Example in parent’s portal
Setting -> Active -> Specific installments, Free amount
Setting -> Inactive
if you do not select a payment method and proceed to save, classter will set the free amount as default value for the payment method.