Cant move anything into my sims 4 mods folder

@0ashlee026  It's possible that your friend's antivirus program is trying to "protect" the Documents directory (with the Sims 4 folder inside) by blocking access.  That's not usually a problem when moving files manually, but it's still possible.  Your friend can try changing the antivirus program's settings, or just disabling it temporarily to see if that is in fact the issue.

Another possibility is that your friend has OneDrive enabled and set to automatically sync the contents of Documents with cloud storage, and either OneDrive is full or it's not working correctly.  Either way, your friend can try disabling the auto syncing of Documents or turning off OneDrive entirely.