I want to know when somebody have read my SMS text

That is not a feature for SMS. Read receipts only show up for iMessages, and only if the person receiving the message has enabled them.

~Lyssa

SMS and MMS are carrier services. Your carrier as well as the recipient's will need to support "SMS delivery reports." If they do, there's a code you have to enter at the beginning to the text message in order to request. E.g. with some carriers it's *0# but don't assume that's what it is for your carrier. "Read reports" don't exist for SMS. For MMS, "read reports" exist as well as "delivery reports" but it would be a different code for "read reports" and you wouldn't get any unless the recipient has "read receipts" enabled. Contact your carrier to find out if and how they support this. (Each "report" is really just one message about the status of the one message it was requested with.)