Launch screens provide a simple initial experience while your iOS app loads. They set the stage for your application, while allowing time for the app engine to load and your app to initialize.
All apps submitted to the Apple App Store must provide a launch screen with an Xcode storyboard.
Customize the launch screen
The default Flutter template includes an Xcode
that can be customized your own assets.
By default, the storyboard displays a blank image,
but you can change this. To do so,
open the Flutter app’s Xcode project
from the root of your app directory.
from the Project Navigator and
drop in the desired images to the
LaunchImage image set.
Apple provides detailed guidance for launch screens as part of the Human Interface Guidelines.