I don't have any important data in my app. But when i read this tutorial i have a few questions ?
Only documents and other data that is user-generated, or that cannot otherwise be recreated by your application, should be stored in the /Documents directory and will be automatically backed up by iCloud.
Do i need to save UserDefaults to iCloud ? And will my app approve if i don't use iCloud ?
And if i need can you show me how to save user default settings ? Because i found only tutorials how to save data from database.
You misunderstand what that is saying.
When a user backup's up their devices using iTunes or iCloud, only certain parts of the app's sandbox is backed up. So there are two important aspects here:
NSUserDefaults is one of the things that will be backed up for you. You don't need to do anything special.
You don't need iCloud support unless your app has a specific need to use it.