How to backup my PC to icloud

Apple offers iCloud Backup for iPhones and iPads but not for Mac or Windows computers.

You can sync some Windows data to iCloud (see below for more information about syncing vs backup). For Windows, see: What is iCloud for Windows? - Apple Support

and Set up and use iCloud for Windows - Apple Support

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 the Apple article: How to back up your Mac - Official Apple Support

And more information on syncing in:

Set up and use iCloud Photos - Apple Support

and

Access and manage your files in iCloud Drive - Apple Support

and

Add your Desktop and Documents files to iCloud Drive - Apple Support

Please see posts about PC data loss before you intall this app. Myself and one other in the past week have experienced this. I've lost a lot of personal data, and am struggling to recover it now.