Hopefully, the information below as well as the associated link will be helpful to you.
About the iOS File System
The iOS file system is geared toward apps running on their own. To keep the system simple, users of iOS devices do not have direct access to the file system and apps are expected to follow this convention.
iOS Standard Directories: Where Files Reside
For security purposes, an iOS app’s interactions with the file system are limited to the directories inside the app’s sandbox directory. During installation of a new app, the installer creates a number of container directories for the app inside the sandbox directory.
Source:
https://developer.apple.com/library/...mOverview.html