From iOS 11, If you set
LSSupportsOpeningDocumentsInPlace to YES and
YES in your
Info.plist, you can access your application Documents directory in the Files application.
<key>LSSupportsOpeningDocumentsInPlace</key> <true/> <key>UIFileSharingEnabled</key> <true/>
For debugging purpose, before iOS 11 you can use FLEX. FLEX also contains a ton of useful debugging features like network request monitor, sqlite database browser etc.