On App Store Connect -> Apps -> Your App -> Monetization -> In-App Purchases there is a message Your first in-app purchase must be submitted with a new app version. Create your in-app purchase, then select it from the app’s In-App Purchases and Subscriptions section on the version page before submitting the version to App Review.
However, on the new version page with "Prepare for Submission" status, there is no place to select the in-app purchase that was created earlier. The section "In-App Purchases and Subscriptions" is completely missing from the version page.
A previous attempt to submit the app resulted in this rejection: We have returned your in-app purchase products to you as the required binary was not submitted. When you are ready to submit the binary, please resubmit the in-app purchase products with the binary.
But the problem is, there is no way to attach the in-app purchase to the new version, as the option is missing. This feels like an internal error on App Store Connect.
The fundamental question is: How can I add an in-app purchase to an existing iOS app on App Store Connect?
Any advice is appreciated!
It's frustrating, but the missing IAP (in app purchase) section on App Store Connect isn't an error (probably), it's a workflow requirement
Here is a short (in reading time) fix
Prep Your IAP: Ensure your IAP is in "Ready to Submit" status with all details complete, including a review screenshot
Clear the Version Page: On your app's version page, you may need to remove any previously attached build
Link the IAP: The "In-App Purchases and Subscriptions" section should now appear. Use the + button to link the IAP
Upload & Submit: Upload a new build of your app (via Xcode or another whatever you use) that includes the IAP functionality, attach it, and submit the entire version for review
If these steps fail, try messaging Apple Developer Support (they might be able to help)