How do I check how much I have left to pay?

I purchased my iPhone at the Apple store back when the iPhone 11 released. I don't know how much I have left to pay for it and I have no clue where to check. I already tried to go to apple.com/bill but all that did was show me my app store purchases/downloads not my monthly bill. Is there anyway to check this? I want to know if I have finished paying off the phones. I did not buy it with the Apple credit card.