Make an in-app purchase in Microsoft Store
When in-app purchases are available for your app or game, you’ll see In-apppurchases on the product’s page. Most in-app purchases will be charged to the payment method selected for your Microsoft account.
Note: Some products manage in-app purchases outside of the Microsoft Store app and might require you to enter your payment information again.
When buying apps or games in Microsoft Store, the plus icon means you can make in-app purchases with that item.
You'll use the same checkout process for in-app purchases as you use to buy apps and games in the Microsoft Store app.