Here is my dilemma/situation:
I download a PDF (or any other type) file from somewhere (i.e Safari, Email, Google Drive, etc.) into an application that can open it (i.e. Documents by Readdle)
I make some adjustments/edit the file using the app (i.e Documents by Readdle).
I go to the Email app and open an email that I want to reply to. I type up my message.
The problem: Now I want to attach that file I just edited in the app (i.e. Documents by Readdle) into this email reply that I am typing up.
How do I do this?