My keypad is not working when I access maps. How do I access my keypad when I a using maps on my iPhone

Try resetting the Maps App.

Close Maps completely from the app switcher window by double clicking the Home button and swiping up the Maps preview pane until it disappears from the screen.

Then restart the device. Hold down the Sleep/Wake and Home buttons at the same time for at least ten seconds, until the Apple logo appears.