Detailed messages on iphone?

I have an old iPhone that I need to get messages off of. I need to have the message authenticated so I need for the messages to display the to and from so I can screen shot it for my records. Does anyone know how to do this? I can't email or forward it to myself because the phone is no longer in service so it has no connection. I would like the threaded message to show my number and their number in the message itself anyone know how to do that

Write them down on paper: D

or connect your phone to a Wi-Fi network

Maybe try to screenshot the messages, then upload them to your computer!