If you are having the Windows 8 license key, just backup the data and install a fresh windows 10 from a bootable USB using the latest iso image from Microsoft website and use the windows 8 license key to activate the windows 10.
Or
You can upgrade if you are using assistive touch by following the below link
https://www.cnet.com/how-to/microsoft-windows-10-free-u...
Good Luck.
Peace.