All Android smart-phones have a pre-installed Messaging app which is usually found on the bottom dock, accessible from all home screens. The Messaging app is generally accompanied by the Phone and Contacts app.
If you can’t find the Messaging app on the home screen, you can look for it in the app drawer, which is accessible through the home screen dock (it is usually represented by a couple of small squares).
Once you open the Messaging app, you can choose to compose a new text message by tapping the ‘Compose new message’ button, which is often denoted by a pen icon.
The New message window generally has two boxes. The top box is for entering recipients while the bottom box is for the message text. You can tap the recipient box and start typing out a contact’s name.
Whenever you tap into a text field (like the recipient or message box) your default keyboard should slide up automatically (if your device does not have a physical keyboard). You can change the default keyboard from within the messaging app. Long press within a text box and select the ‘input method’ option. This will show you all the keyboards installed on your device and you can choose one. If you are using Ice Cream Sandwich or Jelly Bean, this method won’t work. For those iterations, you can swipe down the notification panel while a text box is selected, and tap the ‘Choose input method’ to switch keyboards.
The system will show you matching results as you type and you can tap one of the results to select a contact. Once you have selected a contact, it should appear above the recipient box. Now you can start entering the message text by tapping the bottom box.
Once you have typed your message, you simply have to press the send button. Now if you press the back key, the messaging app screen will show you a contact thread for the text you just sent.