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

https://wiki-wire.win/index.php/Why_Do_I_Feel_Safer_Not_Typing_My_Card_Number_on_Random_Sites%3F

Carrier billing lets you buy apps, games, or subscriptions and have the cost added directly to your phone bill. If you’re on a monthly plan, the charges appear on your next statement