Purchases within the App Store:

Commission of 25% (general) or 10% (special programs)

5% fee if you use Apple’s payment system

App purchases on the App Store, but directed outside the store:

No fee if the routing involves static text (no clickable link/button)

15% fee if the owner of the app puts a button/link and directs to payment on his own website (outside the app environment)

Alternative stores:

5% of Core Technology Commission

https://www.theverge.com/news/850061/apple-brazil-third-party-app-stores-external-payment-systems