Accepting partial payments on orders

Bowlers can signup for a 32 week league and select to pay all now, pay by the week with auto draft, or full invoice to the customer and they can make payments in any amount they want whenever they want until the end of the league season. Example: customer signs up and is given an email invoice for the entire amount. They can pay with the button but they can choose how much they want to pay. The total then adjusts. Let me know how to set this up so customers can pay on the balance of their account if not selecting “pay all at once” or pay auto weekly.