Samsung Galaxy S6 User Manual page 132

Enable Enhanced Messaging
1. From home, tap Apps
2. Tap More > Settings > Enhanced messaging.
3. Tap the ON/OFF switch to enable Enhance messaging.
4. Set options:

Image resize: Set the standard size of images sent with Enhanced messages.

Send as SMS/MMS messages: Send your Enhanced messaging messages as text or
multimedia messages when Enhanced messaging is unavailable.

Registered information: View and set the registered information for your phone number.
Messaging and Internet
> Messages .
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