How can i access hidden files/System files/App files in Lumia 540 having windows 8?

[souvenir hacen]

I want to find a file downloaded by an app but not showing ready in app folder.

 

[N_LaRUE]

Apps in Windows Phone are sandboxed, meaning the files and everything associated with them are not accessible.

With some apps, files can be saved to SD cards where you can access them, in others it's cloud access.

It's part of the security of Windows Phone.

There is a file manger available but you are still limited to what you can access.