Best practices
Launch instantly.
If the platform requires it, provide a launch screen.
If you need a splash screen, consider displaying it at the beginning of your onboarding flow.
Restore the previous state when your app restarts so people can continue where they left off.
Launch screens
Downplay the launch experience.
Design a launch screen that’s nearly identical to the first screen of your app or game.
Avoid including text on your launch screen, even if your first screen displays text.
Don’t advertise.
Platform considerations
iOS, iPadOS
Launch in the appropriate orientation.
tvOS
In a live-viewing app, consider automatically starting playback soon after people start the app.
visionOS
Consider launching in the Shared Space even if your app is fully immersive.
For the complete guidance, including worked examples and illustrations, see the canonical page: https://developer.apple.com/design/human-interface-guidelines/launching