When you create a new app with Flutter, the default package name is com.example.your_project_name. This must be changed before you upload your app to the stores. Instead of com.example, you should use your own domain, if you have one, or some other unique identifier. This package name must then be set in the AndroidManifest.xml file in the manifest node, and in runner.xcworkspace in the Bundle Identifier setting.
The iOS bundle identifier and the Android package name do not need to be the same; just make sure they are both unique in the respective stores.
When you change the package name in the AndroidManifest.xml file, you also have to update the MainActivity.kt file to avoid compilation errors.
The android:label property contains the name of the app that your users will see on their screen, so it's particularly important that you choose a good name for your app here. On iOS, you perform the same with the Display Name property.
Another setting...