You can check for updates on Windows 10 by going to your "Update & Security" menu. If an update is available, it'll begin ...
You can update Windows through the Settings app on your computer, although your PC probably downloads updates automatically.
Windows 10 KB5066791 is the last update if you don't subscribe to ESU (Extended Security Updates). Download it today.
When certain prerequisites are not met, the “Enroll Now” option may not appear in Settings → Windows Update on Windows 10.