All SaaS (Sofware as a Service) companies that you will go for publishing apps in the Apple App Store will charge a fee like Mobiroller.
The main reasons for this are;
1. IPA file being configured by companies,
2. The requirement of having the necessary hardware and allocating an employee workforce for this (“…..” code information, the need to use a Mac device, etc.)
3. The additional benefit status on the Mobiroller side is the reflection of the design and updates you made, except for the basic issues such as your app’s logo or name after uploading your app to the Apple App Store. You do not need to send an update with every change.
If you want to do it by yourself, you should have prepared an app-independent from the other platforms.