Will I lose all the backup in iCloud if I erase my Mac?
If I remove my old Imac, will I lose all of its backed up memory in Icloud
[Re-Titled by Moderator]
iMac (2017 – 2020)
It is not possible to backup a Mac to iCloud.
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.
If you are asking about data synced from the Mac to iCloud, it will not be affected if you perform the steps listed in What to do before you sell, give away, trade in, or recycle your Mac - Apple Support