CloudKit uses the user’s iCloud storage for private containers and bills the developers (although it’s usually free) for "public" CloudKit containers[1]. [1]:

CloudKit uses the user’s iCloud storage for private containers and bills the developers (although it’s usually free) for "public" CloudKit containers[1]. [1]: https://developer.apple.com/icloud/cloudkit/ https://developer.apple.com/icloud/cloudkit/