Question

I am facing one problem while fetching a file which is downloaded from an other app into my app.
Is it possible or not?

Answer 1

I highly doubt you could actually access other’s application data (downloaded from the internet) without a jailbroken device:

For security reasons, iOS places each app (including its preferences
and data) in a sandbox at install time. A sandbox is a set of
fine-grained controls that limit the app’s access to files,
preferences, network resources, hardware, and so on. As part of the
sandboxing process, the system installs each app in its own sandbox
directory, which acts as the home for the app and its data.