Samsung Galaxy S® 6 / S® 6 edge - Create and Send a Text Message

From a Home screen, navigate: Apps > Samsung > Messages.
These instructions apply to Standard mode only.
If prompted to change default messaging app, tap YES > OK to confirm.
From the Inbox, tap the New message icon (lower-right).
Tap COMPOSE (upper-right).
From the Recipient 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.
To add an attachment:
1. Tap the Attach icon (lower-left).
2. Locate then select the appropriate attachment.
  If necessary, select the attachment type (e.g., CAMERA, GALLERY, OTHER) located at the bottom.
From the Enter message field, enter a message.
Tap SEND.