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

https://fair-wiki.win/index.php/What_Can_I_Buy_with_Pay_by_Phone_Billing%3F

Carrier billing lets you buy apps, games, or subscriptions and have the cost added to your monthly phone bill or taken from your prepaid credit. It’s a simple way to pay without entering card details, making small purchases easier on your phone.