how to create a backup from 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.

Also see: https://support.apple.com/mac-backup

And more information on syncing in:

Set up and use iCloud Photos - Apple Support

and

iCloud Drive FAQ - Apple Support

Guellermg wrote:

How do you create a backup of your computer using iCloud

iCloud does not backup a Mac. The article you came from talks about Time Machine. That is your macOS solution.

iCloud will sync some content for you. The iCloud Drive itself and if enabled, the Desktop and Documents folder(s).