What is the best way for an entire text message exchange in an iPhone and in Messenger be archived?

Have you considered doing a screen shot???

I have read that there is a way to save them to your computer without a 3rd party app, but I’ve not tried it so I can’t explain this one.

All of our texts are automatically saved for years to come, so there should be a way to access them!!!

Send it to your email and save it there or whereever you want on your computer.

You can send the screen shots to your email address too, but screen shots are a bit clunky.