Carrier billing lets you buy apps, games, or digital content and charge the...

https://titusscoolinsight.capitaljays.com/posts/is-pay-by-phone-billing-the-same-as-a-mobile-wallet

Carrier billing lets you buy apps, games, or digital content and charge the cost directly to your phone bill. If you have a monthly plan, the purchase appears on your next bill. For pay-as-you-go users, the amount is deducted from your available credit