I have completed the application except for anything to do with payment. Im not sure where to go from here. I have been beta testing but now Im ready to submit to app store. will there just be an option for users to subscribe when my app is displayed? or do I need to insert apples api or something into my app and then accept payment through stipe or something like that?
will there just be an option for users to subscribe when my app is displayed?
You mean purchase? If you make your app PAID in the App Store Connect then costumers will need to purchase your app via App Store (Apple handles everything here and you don't need to do anything else), however if your app has subscriptions or other purchases that unlocks or enables additional content, then you will need to implement this by yourself in your app via Apple StoreKit. Since you are using React-native, you will need a third party solution to handle the communication between your app and Apple's StoreKit.