Saving a text file from external source to my app Objective C

Abstract Question here I guess

I have an idea for an app that parses .txt files and outputs info based on what is contained in the file. My question is how would I go about getting the text file into my app for example if the text file was attached to an email?

This is the only hurdle I have to get clear in my mind before I begin. So here's a real life scernaio -

I have email with text file, I want to open my app and say import file. I need to get that text file from my email into the app so I can manipulate it.

Not sure this is possible, hopefully somebody can let me know or suggest a workaround.

Thanks in advance!

via Chebli Mohamed