AppDelegate Device Id.swift

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        print("Notification registration is success.")
        
        if #available(iOS 10.0, *) {
            let deviceTokenString = deviceToken.reduce("", {$0 + String(format: "%02X", $1)})

            print(deviceTokenString)
        } else {
            let tokenParts = deviceToken.map { data -> String in
                return String(format: "%02.2hhx", data)
            }
            let deviceTokenString = tokenParts.joined()
            
            print(deviceTokenString)
        }
    }

    func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
        print("Notification registration is fail: \(error.localizedDescription).")
    }