Message Center Missing I cannot find the message center of my galaxy s4 phone. I know exactly where it is supposed to be, however it is not there. The section reads: Text Message (SMS) settings Delivery reports Manage SIM ...
I am not sure of what you are looking for exactly, but i find this and it may help you :

How to set up your mobile phone for SMS

An SMS is a text message which can be sent to other mobile phones. You'll be able to send and receive SMS as soon as you've inserted your SIM card into your mobile phone. If this isn't the case, you can set up your mobile phone for SMS manually.

1.

Find "Settings"

-Press Messaging.
-Press the Menu key.
-Press Settings.


2.

Save the message centre number

-Press Message Centre.
-Key in +41794999000 and press OK.


3.

-Return to the Home screen


Source : Device support

Hope it will help.