Most apps and games downloaded from Microsoft Store on Windows 10 are placed on a special folder (WindowsApps), which the user probably won't have access.
That said, in case you want to use mods in a game, you'll likely need access to the it's files. Even though Microsoft introduced the option to enable mods, not all developers have adopted this yet (if some ever will). This document presents an alternative to get access to the files you may need.
This is basically a copy-paste of u/WiredRawdy's reddit post.