Margin

 import "package:flutter/material.dart";

void main() {
  runApp(const FlutterApp());
}

class FlutterApp extends StatelessWidget {
  const FlutterApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: "Hello World",
      theme: ThemeData(
        primarySwatch: Colors.deepPurple,
      ),
      home: const DashBoardScreen(),
    );
  }
}

class DashBoardScreen extends StatelessWidget {
  const DashBoardScreen({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text(
          "Hello HEER",
          style: TextStyle(fontWeight: FontWeight.bold),
        ),
        centerTitle: true,
        backgroundColor: Colors.grey,
      ),
      /*body: Padding(
        //padding: EdgeInsets.only(top: 11, left: 45),
        padding: EdgeInsets.all(45),

        child: Text("Hello World!", style: TextStyle(fontSize: 25),),
      ),*/

      body: Container(
        color: Colors.blueGrey,
        margin: const EdgeInsets.all(11.0),
        child: const Padding(
          //padding: EdgeInsets.all(11),
          padding: EdgeInsets.only(top: 21, left: 34),
          child: Text(
            "Hello World!",
            style: TextStyle(fontSize: 25, color: Colors.white),
          ),
        ),
      ),
    );
  }
}