How will I used my mobile billing to payment method
I want to use my mobile money account to pay my bills
Question marked as
Which bills? For apps and media, or for ApplePay?
Read the linked document about Availability of mobile phone billing as an Apple ID payment method - https://support.apple.com/HT205102
ApplePay requires a credit card.
Set up Apple Pay - Apple Support - https://support.apple.com/HT204506
"Here's what you need to use Apple Pay in supported regions:
Your eligible device
A supported card from a participating card issuer
The latest version of iOS, watchOS, or macOS
An Apple ID signed in to iCloud2"