edit payment method for AppleTV

As described in the Related Article, you can set any valid payment method, or multiple payment methods, for your Apple ID account. Any purchase on that account will be charged to the payment method. You can’t designate a special payment method for a certain kind of purchase, but you can change the primary and secondary method at any time by changing the order.

If you don’t have an Apple device to manage the payment method, then there are alternatives.