Carrier billing lets you buy apps, games, or subscriptions and charge the cost...

https://www.bookmark-friend.win/carrier-billing-lets-you-pay-for-apps-games-or-services-using-your-phone

Carrier billing lets you buy apps, games, or subscriptions and charge the cost directly to your monthly phone bill or subtract it from your pay-as-you-go credit. It’s a simple way to pay without needing a credit card or separate account