A Microsoft file hosting and synchronization service.
OneDrive is not a backup, it’s a cloud location of your data.
.
The default installation of Office 365 and its OneDrive component uploads all the contents of the PC \My Documents\ folders to OneDrive, (syncs) and there will be a OneDrive folder in File Explorer containing all the OneDrive content. And in Word etc the default Save location is set to OneDrive.
No docs will be saved to the local PC.
If Office 365 is not installed/activated and a new PC will have a pre-installed 365 Family trial version.
The only other OneDrive is the win 11 OneDrive that has a limited space of 5gb and nothing is saved to that unless the user explicitly save docs to that