Ejemplo de AppBar con propiedades en Flutter

ejemploappbar.dart

import 'package:flutter/material.dart';

void main() => runApp(const MiAplicacion());

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

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      debugShowCheckedModeBanner: false,
      home: EjMiAplicacion(),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        automaticallyImplyLeading: true,
        title: const Text("Ejemplo de appBar"),
        centerTitle: true,
         actions: [
          IconButton(
            icon: const Icon(Icons.search),
            onPressed: () {
            },
          ),
          IconButton(
              icon: const Icon(Icons.more_vert,),
              onPressed: () {
              },
          ),
           IconButton(
              icon: const Icon(Icons.add_card,),
              onPressed: () {
              },
          ),
        ],
        toolbarHeight: 70,
        shape: StadiumBorder(),
        elevation: 8,
        backgroundColor: Colors.blue,
        shadowColor: Colors.blueGrey,
      ),//fin de appBar
      drawer: const Drawer(),
      body: const Center(
        child: Text(
          'Inicio Diego Diaz',
          style: TextStyle(fontSize: 24),
        ),
      ),
    );//fin de Scaffold estructura
  }
}

Trabajando con AppBar
Diseño

Resultado de mi codigo en flutter

Link de referencias
https://api.flutter.dev/flutter/material/AppBar-class.html
https://codesinsider.com/flutter-appbar-example-tutorial/?expand_article=1
https://dartpad.dev/?id=75f592c1360255ea44b11943258eaaac