The website I stole these steps from is here, and they have other instructions for how to do the SFC scan before Windows starts as well (I snagged screenshots below in case something happens to the website):

https://windowsreport.com/corrupted-system-files-windows-10/

Fixing corrupted files on Windows 10

Using the DISM (Deployment Image Servicing and Management) Tool

Running a SFC scan from Safe Mode