Releasing in iOS has some higher complexity when compared to Android. Although you can test on your own device when developing, making an app public requires you to have a valid Apple Developer account with the ability to publish on App Store, as it's the only supported app publishing channel.

Like Android, first, we need to review some information about the app in the Xcode project settings, like we did in AndroidManifest.xml. And after that, we will be able to create an app archive ready for publishing on the App Store.

Also, check the presence of the GoogleService-Info.plist file in the ios/Runner directory (see Chapter 8, Firebase Plugins, to remember how to import it inside Xcode).