How to make my messages tell me if the person has read the message?

I have an iPhone 5 and i've seen on other people's that you can see whether the person you've sent the message to has read your message or not? Anyone know how to turn this setting on please?

Pretty sure what youre talking about is when it says "Read: (time)" under their message. The person youre texting has to have their "send read receipts" setting on for you to be able to see it.