From a Home screen, navigate: Essentials > Messaging. Swipe left or right to access apps; steps apply to the default Home mode.
From the Inbox, tap the Compose icon (located in the lower-right).
From the To field, enter a 10-digit mobile number or a contact name. As the number or contact is entered, a matching contact may appear and can be selected at any time.
From the Enter message field, enter the message. To add a subject:
From the message field, tap the Menu icon (located in the upper-right).
Tap Add subject.
Enter a subject.
To add an attachment:
Tap the Attach icon.
Tap the attachment type (e.g., Picture, Audio, etc.).