Does it show it every time you send a message and right after the message is sent? If so, you cannot turn these off.

If you receive this as a text sent back to you, it is under the individual message settings menu.

anyone know how to make theses texts stop???? iv looked in the message settings and cant find anything that turns off these texts.....after every text i send it says "message to (number i texted to) succeeded,any help/advice is more then welcome,thanks.