I want to delete a game from icloud

If you have data from a game saved in iCloud, you can find and delete that data here:

Settings → Apple ID → iCloud → Manage Storage → find the game, tap in and delete.

Please note that all data obtained in the game will be deleted. This will NOT delete the app from the phone, but just delete the app's data stored in iCloud. If you want to delete the game, find the app icon on your Home Screen, long press and select Delete App.

You can find more information about how to manage your data in iCloud here:

Manage your iCloud storage - Apple Support