how do I upload a debit card on my iphone when it kept reqisting for a credit card?

Changing/removing payment info : Change or remove your Apple ID payment information in the iTunes Store - Apple Support

For a card to have a chance of being accepted it needs to be registered to the same name and address (including format and spacing etc) that you have on your iTunes account, and have been issued by a bank in the country where you are (and therefore the country which is on your iTunes account).

But you may not be able to use a debit card, they seem to be being accepted less-and-less by iTunes.