The last build you upload to App Store Connect and submit to the App Store should be product quality and pass App Store Connect validation tests.
Before submitting your final candidate, go to App Review to review the App Store and human interface guidelines. For watchOS apps, also read Preparing Your watchOS App for Submission.
You must provide an App Store icon. If you haven’t already done so, add an App Store icon to your Xcode project.
You may need to enter additional information in App Store Connect before you can submit your app to App Review. After your app is uploaded or released, you can’t change some of this metadata, so it’s important to choose your settings carefully. For the metadata that is required (or can’t be changed later), go to Required, localizable, and editable properties in App Store Connect Help.
In Xcode, prepare your app for distribution and then create an archive of your app.
Immediately after creating the archive, validate the archive and fix any validation errors before continuing.
It’s recommended that you submit a build you distributed for testing to App Review. For iOS, tvOS, and watchOS apps, upload your app to App Store Connect and then distribute the app using TestFlight to test your builds. For macOS apps, distribute your app to registered computers or distribute your app outside the Mac App Store before you upload it to App Store Connect.
To submit the final build of your app to App Review, go to Publish your app in App Store Connect Help.