Carrier billing lets you buy apps, games, or digital content using your mobile...

https://shanesexpertinsights.inkharbory.com/posts/does-carrier-billing-work-if-i-switch-to-a-new-phone

Carrier billing lets you buy apps, games, or digital content using your mobile phone. Instead of a credit card, the cost is added to your monthly phone bill or taken from your pay-as-you-go balance. It’s a simple way to pay without entering card details.