Carrier billing lets you buy apps, games, or digital content and charge the...
https://meet-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 have a monthly plan, the purchase appears on your next bill. For pay-as-you-go users, it’s deducted from your available credit