the "secure folder" can be hidden/hidden on the start screen as well as on the app screen. while the folder is hidden, it can't be opened either. the only way to make it visible again is via the usual settings themselves. to make a change, the password/PIN/pattern for the "secure folder" must be present.
- Tap on Secure Folder
- Open the Menu
- Tap on Settings
- Enable or disable Show icon on Apps screen