The article in the link below describes how to use 'Voice Memos' to easily record something on your iPhone. You don't even have to look to find the app on your iPhone. Pick it up, hold the Home Button till Siri opens, then say " Siri", "open Voice Memos." The app will open and you just tap the big red button and start talking.
This looks to be mighty handy to make a quick note of something you don't want to forget.
This works on the iPhone 6 and newer models. And it works on the iPhone 5 if it is running iOS 7.