iCloud
When I store documents in iCloud, is the same information retained in my desktop mac
iMac 27″, macOS 10.14
Question marked as
It may be or may not be. If you don't turn on Apple menu > System Preferences > Apple ID > iCloud > Optimize Mac Storage then there will always be a local copy. If you do turn that option on there may or may not be -- see the wording for that option in the partial screenshot of that System Preferences window below: