Windows hides certain files and folders by default to prevent the unexperienced users from messing with them. In some situations however it is necessary to view them, e.g. to backup some data from the hidden App Data folder.
So to make hidden files visible, open the Control Center and head to Appearance and Personalization > Folder Options. Open the View tab and under Advanced Settings check the Show hidden files, folders and drives checkbox. Confirm with Apply or OK and every hidden file and folder will be visible as transparent item in the explorer from now on.