Lifting your finger to type each letter is so yesterday! Try swiping - or as Apple calls it "Quick Path."
When you swipe type, you don’t have to lift your finger from the keyboard between key presses. It’s especially helpful when you’re typing one-handed. It’s also usually faster than two-handed typing due to the much higher error rate when you use your thumbs.
First, enable this feature:
Settings > General > Keyboard
iPhones - enable
Slide to Type
iPads - enable
Slide on Floating Keyboard to Type