Flutter Launcher Icons has been designed to help quickly generate launcher icons for both Android and iOS: Flutter Launcher Icons

To start with,

• Add the dependency flutter_launcher_icons: "^0.9.2" into your pubsec.yalm file.

dev_dependencies:
  flutter_launcher_icons: "^0.9.2"

• Within pubspec.yaml file specify the path of the icon you wish to use for the app and then choose whether you want to use the icon for the iOS app, Android app or both.

dev_dependencies:
  flutter_launcher_icons: "^0.9.2"

flutter_icons:
  android: true
  ios: true
  image_path: "assets/icon/icon.png"

• Run the package, execute the command on the terminal to Create app icons:

$ flutter pub get

$ flutter pub run flutter_launcher_icons:main

F:\AndroidStudioProjects\FlutterProject\SportsFlutter\sports_flutter>flutter pub get
Running "flutter pub get" in sports_flutter...                       881ms

F:\AndroidStudioProjects\FlutterProject\SportsFlutter\sports_flutter>flutter pub run flutter_launcher_icons:main
  ════════════════════════════════════════════
     FLUTTER LAUNCHER ICONS (v0.8.0)
  ════════════════════════════════════════════

• Creating default icons Android
• Overwriting the default Android launcher icon with a new icon

✓ Successfully generated launcher icons