ICloud payment
Why can’t I use Apple Pay to pay for my ICloud storage?
iPhone XR, iOS 12
ApplePay can't be added as a payment form for the iTunes and App Stores.
Payment methods you can use in the iTunes Store, App Store, and iBooks Store - https://support.apple.com/HT202631 - debit cards are not accepted in all countries and even if they are accepted they may not be accepted for all types of purchases.