APN configure for Firebase Cloud Messangers

Firebase Push Notifications.swift

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // CONFIGURE PUSH NOTIFICATION
    let authOptions : UNAuthorizationOptions = [.alert, .badge, .sound]
    
    UNUserNotificationCenter.current().requestAuthorization(
        options: authOptions,
        completionHandler: {_,_ in })
  
    UNUserNotificationCenter.current().delegate = self
    application.registerForRemoteNotifications() // here your alert with Permission will appear
    
    // CONFIGURE FIREBASE PROJECT
    FirebaseApp.configure()
}

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    Messaging.messaging().apnsToken = deviceToken
}