#8. Hide the keyboard
Sometimes, when you’re responding to a message, you want to see more of the original message. Maybe you forgot the exact question you’re trying to answer, or you want to refer to something specific. No matter the reason, all you have to do is touch the message above the keyboard and swipe down to hide it.
It will be visible as RE: subject of message at the bottom of your screen. Just tap to bring it back and continue your reply.
See the other Email shortcuts… Secret Mail shortcuts: Ten gestures to speed up your iPhone email! | iMore.