As many people inquire whether there it is possible to print the text messaging conversation from iPhone, I would like to introduce a couple of different ways to print iPhone text messages from Mac and Windows computers.
If you are using Mac and you have Apple Message configured for your account, you can print text conversations because all of your messages will be available on the computer as well as your iPhone. All you have to do is open the conversation on your computer, and choose File and then Print.
If you are using a Windows, you have a couple of options.
One is to take screen shots of the text conversation and mail them to yourself and then print the screenshots from computer. If you have a large number of messages and very long text conversation, it may require quite a number of screenshots.
Read more at Different Ways to Print iPhone Text Messaging Conversation