Carrier billing lets you pay for apps, games, or digital content by adding the...

https://andresssmartcolumns.talesignal.com/posts/how-does-pay-by-phone-work-on-pay-as-you-go

Carrier billing lets you pay for apps, games, or digital content by adding the cost to your monthly phone bill or deducting it from your prepaid credit. It’s a simple way to buy without needing a credit card or separate payment app