What does it mean if my My Apple Pay says balance

To see your Card Balance, open the Wallet app on your iPhone and tap Apple Card. The Card Balance shows below your card. Card Balance includes all new spending and any remaining monthly balance. If you have Apple Card Monthly Installments, then your balance includes the newly billed monthly installment.

How to make Apple Card payments - Apple Support

Precise words are important.

”Apple Pay” is a method of paying wirelessly. There is no specific debit or credit associated with Apple Pay, only transaction amounts.

“Apple Cash” and “Apple Card” may have balances.