How to attach files to emails on iPhone running iOS 8? 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?
Documents by Readdle lets you send any arbitrary file over email. Select the file in Documents, tap Actions, then Mail to. This composes a new email with the file attached.

Upgrade to iOS 9 and you can attach arbitrary files from Apple's mail client. Documents can export files to iCloud drive for easy attachment or you can just save the file to iCloud drive from the get go and skip the Documents unless it ads value to your workflow.