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

https://camilassmartthoughtss.opalvector.com/posts/why-does-my-checkout-ask-me-to-confirm-by-text-message

Carrier billing lets you buy apps, games, or digital content and have the cost added directly to your monthly phone bill or taken from your pay-as-you-go balance. It’s a simple way to make payments without credit cards or separate accounts