Carrier billing lets you buy digital goods or services and have the cost added...

https://www.thecoastlandtimes.com/sponsored-content/pay-by-phone-how-carrier-billing-quietly-became-an-everyday-payment-method-4a6c068e/

Carrier billing lets you buy digital goods or services and have the cost added to your monthly phone bill or taken from your prepaid credit. It’s a simple payment option that doesn’t require a card or separate account