1. iMessage is built into iOS versions 5 and later, and allows you to send unlimited text, photos, videos, locations, and contacts using Wi-Fi or cellular data from your iPhone or iPad.
   
2. From the Home screen, tap Settings.
   
3. Tap Messages.
   
4. Tap the "iMessage" toggle to turn on or off.
   
5. Press the Home button to return to the home screen.