Authorization and payment in iOS applications?

Question

iOS

Is it possible to authorize on the first screen in an iOS application using email and password? Without authorization, the functionality of the application is not available.
Is it possible to top up an account in the web version of the service using In-App Purchase? That is, accept payment through Apple, and provide a service outside the application. It is planned to replenish a single account, which will be debited through the web and iPhone version. Debiting from the account in the service will be carried out both from the mobile phone and the web version.

Answer 1

About
>Is it possible to authorize on the first screen in an iOS application using email and password? Without authorization, the functionality of the application is not available.
Yes, of course it's possible. But I hope there will be a Register button. Otherwise, there will be problems with checking the application.
Is it possible to top up an account in the web version of the service using In-App Purchase?
With the second one, no. An excerpt from the App Store Review Guidelines. Google it and read it carefully. After that, all questions will disappear. 11.3
Apps using IAP to purchase physical goods or goods and services used outside of the application will be rejected
11.4
Apps that use IAP to purchase credits or other currencies must consume those credits within the application
There will at least be problems with the above points