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

https://judahsuniqueop-eds.lumenforgex.com/posts/can-i-turn-off-carrier-billing-on-my-phone-plan

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