back-up to iCloud
May I back-up my mac air on to iCloud?
Question marked as
Top-ranking reply
Apple offers iCloud Backup for iPhones and iPads but not for Mac computers.
It is possible to sync data from a Mac to iCloud if you turn on those options (e.g., iCloud Photos, iCloud Drive including the Desktop & Documents option). Syncing has some of the benefits of a backup (and the benefit of being offsite) but is not the same as a backup. Major differences include the fact that not everything on your Mac can be synced and the fact that if you delete something, accidentally or otherwise, there is only a limited time period (30 days in most cases) during which it can be recovered.
Also see: https://support.apple.com/mac-backup
And more information on syncing in:
Set up and use iCloud Photos - Apple Support
and