Nokia Lumia 635
Set up your phone for text messaging
A text message is a message that can be sent to other mobile phones. Your phone can send and receive text messages as soon as you've inserted your SIM. If this isn't the case, you can set up your phone for text messaging manually.
1. Find "settings"
Press the message icon.
Press the dots in the bottom right corner of the display.
Press settings.
2. Save the message centre number
Press the field below "SMS centre number".
Key in +6421600600 and press save.
3. Return to the home screen
Press the home icon to return to the home screen.