As a convention, the App ID is in the form of a reversed addresse, for example,
com.example.MyPushApp. The App ID must not contain a wildcard character ("*").
Enter a name for your App ID, and, under App Service, select Push
Notifications.
Accept the default App ID prefix, or choose another one.
Under App ID Suffix, select Explicit App ID, and enter your
iOS app's Bundle ID.
This string should match the Bundle Identifier in your iOS app's
Info.plist.
Select Continue.
Verify that all the values are correct. Push Notifications should be enabled, and
the Identifier field should match your app's Bundle Identifier (plus App ID Prefix).