You can send iMessages to phone numbers or email addresses if the recipient has a device that supports iMessage. Before you can send and receive iMessages, you need to set up your tablet for iMessaging.
Tap the message icon.
Tap the new message icon.
Tap To: and key in the first letters of the recipient's name.
Tap the required contact.
Tap the text input field and key in the required text.
Tap the send icon.
You can also send pictures, video clips, audio files and different effects in your iMessage. Follow the instructions on the screen to send your iMessage with the required content.