pass data one screen to other in flutter

// First Screen

import 'package:flutter/material.dart';
import 'package:garment_ecommerce/secon_screen.dart';

class FirstScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: TextButton(
        onPressed: () {
          Navigator.push(
            context,
            MaterialPageRoute(
              builder: (context) => SecondScreen(
                userName: 'UserName',
              ),
            ),
          );
        },
        child: Text('Second Screen'),
      ),
    );
  }
}

//
Second Screen

import 'package:flutter/material.dart';

class SecondScreen extends StatelessWidget {
  final String userName;
  const SecondScreen({Key key, this.userName}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text(userName),
      ),
    );
  }
}