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

https://juliet-wiki.win/index.php/How_Do_I_Decide_When_to_Use_Carrier_Billing_vs_a_Card%3F

Carrier billing lets you buy apps, games, or digital content and charge the cost directly to your phone bill. If you’re on a monthly plan, the purchase shows up on your next bill