Flutter - How to Change App and Launcher Title in Different Platforms

<application
  android:label="Your android app title"
  android:name="${applicationName}"
  android:icon="@mipmap/ic_launcher">

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'App Title',
      theme: ThemeData(
        scaffoldBackgroundColor: Color(0xFFDEE9F9),
        textTheme: TextTheme(
          headline3: TextStyle(
            color: Colors.black,
            fontSize: 20,
            fontWeight: FontWeight.w600,
          ),
        ),
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      initialRoute: home,
      routes: {
        checkBox: (context) => const GradientCheckBox(),
        home: (context) => const Home(),
      },
    );
  }
}

<key>CFBundleDisplayName</key>
<string>Your iOS App Title</string>

<meta name="apple-mobile-web-app-title" content="your web app title">
<title>your web app title</title>

<meta name="description" content="Your App Description">

name: Your App Title
description: Your App Description

publish_to: 'none' 

version: 1.0.0+1

environment:
  sdk: ">=2.16.2 <3.0.0"