In fact, CloudKit is a layer on top of iCloud. With CloudKit, you can work with structural data. With iCloud, do you probably mean "iCloud Document Storage"? In both cases, you can do this with both Swift and Objective C. The iCloud document repository lasts longer, which is probably why most samples are in Objective C.
With CloudKit, you can process records and data files (like CKAsset). This data will be bound to the containers that you registered in your application. You will not be able to access the data of another application (if the application does not belong to you and you have added a container)
, CloudKit iCloud, 1-1:
https://developer.apple.com/library/ios/documentation/General/Conceptual/iCloudDesignGuide/Chapters/iCloudFundametals.html#//apple_ref/doc/uid/TP40012094-CH6-SW1
, Swift CloudKit, - http://github.com/evermeer/EVCloudKitDao