Onesignal

OneSignal allows you to send push notifications

First Import import 'package:onesignal_flutter/onesignal_flutter.dart';

Later put this code:

// class _MyApp extends State<MyApp> {

  @override
  void initState() {
    super.initState();
    initPlatfotmState();
  }

  Future<void> initPlatfotmState() async {
    OneSignal.shared.setAppId("oneSignalAppId");
  }