The new Predictive Text feature in iOS 8 can be useful for helping you quickly peck out sentences when working with one finger, however, sometimes the extra space above the keyboard just gets in the way. The good news is that in those situations it can easily be hidden or turned off entirely without having to resort to a trip all the way into your keyboard settings.
If you place your finger on the Predictive Text bar above the keyboard, and swipe downward, the bar can be dragged down into a hidden position. You’ll see a small horizontal line representing the hidden bar, and reversing the gesture by tapping and swiping back upwards will return the bar into view. Alternatively, if you’d rather switch the Predictive Text bar off entirely instead of just hiding it, you can tap and hold on the Emoji or language button near the bottom left corner of the keyboard to bring up the keyboard selection options, at the top of which will be a “Predictive” toggle; this mirrors the “Predictive” option found in Settings, General Keyboard.