Is there any way you can tell if your text messages have already been read?!

Is there any way you can tell if your text messages have already been read?

Please help

1 month ago
like the ones you send to other people

On my fone if u have new messages and they havent been read a litle envelope will be at the top of ur screen. and wen u go to messsages there will be a sign saying that. If they have been read u can tell.Cuz its the opposite.