Unable to require Face ID for apps on iPhone 15

It’s possible that Face ID hasn’t been set up on your iPhone, or that something caused the settings to reset. If you’re noticing that apps no longer prompt for Face ID—and there’s no option to enable it—it might be due to one of the following reasons:

1. Face ID is not set up: Go to Settings > Face ID & Passcode and make sure Face ID is fully set up. If it’s not, you’ll need to set it up again.
2. Face ID is disabled for apps: In the same section (Settings > Face ID & Passcode), scroll to the “Use Face ID For” section. Check if options like iPhone Unlock, iTunes & App Store, or Other Apps are disabled. If the “Other Apps” list is missing or greyed out, this could indicate a bug or restriction.

See the pic below here where you can find out which apps have access to Face ID. If you do see this on your iPhone, then you will have to go into the settings of the App (Not iPhone Settings). You may also delete the app and reinstall it.

Do you happen to be under 13? If so, child accounts do not have the capability to lock or hide apps.