Monitoring Your Student's Phone for "Vault "Programs.
Vault Apps are inconspicuous apps on a Droid, iPhone or iPad that are used to hide/store inappropriate photos and videos. Tips on determining whether an app is a Vault App.
Use the Storage & iCloud Usage feature on your iPhone or iPad to look for apps with unusually large amounts of data. Apple’s instructions on how to check the storage - https://support.apple.com/en-us/HT201656
If you find two or more of the same type of app on your child’s phone (i.e. 2 calculator apps), be proactive. Type the exact name of each app into the App Store to confirm whether they are both legitimate. An illegitimate app would likely be named “Secret Calculator” or “Private Calculator” or something similar.