How to make payments to your Appl Pay?

You can transfer funds into Apple Cash account from a demand deposit account such as a checking account or savings account.

If you don’t have an account, you can give cash to a friend or relative and they can send funds to your Apple Cash account using Messages (iMessage).

The two Apple Support articles I shared below explain how.

Add money to Apple Cash - Apple Support

Send and receive money with Apple Cash - Apple Support

There is no such thing as an Apple Pay account. What are you trying to do? Add funds to Apple Cash? Pay your Apple Card? Something else?