Audio File On Voice Memos App

Hi. I have a large audio file in my voice memos app on my iphone4. My OS is 7.1.2 which my phone says is the most recent. I thought an iphone4 could upgrade to OS 8. Is that right or wrong?

The audio file is over an hour long, a recorded meeting. It is larger than 25 MB which means my Yahoo email account cannot transfer it. I have dropbox and icloud, but when I tried dropbox, the only export option icons that appeared were email and message. Neither worked.

Is there a way to transfer the audio file to my icloud so that another person can access it? And then, if that is possible, how do I allow access to ONLY that file, and not other personal files? Thanks.