TEXT MESSAGE PDF. OR PRINTOUT

Hi renée4485

welcome to the Apple (user-to-user) Community!

Re: "Is there any way to get a printout or possibly a pdf. file

of all the text messages between yourself & another iPhone user?"

We do not know which iOS version you are using on your iPhone, (or the MacOS version on your Mac).

If you copy and paste the text conversations to a document (eg: "TextEdit" or "Notes" on your Mac) you can likely Choose "export" from the app's File menu to produce the .pdf file you are wanting.

There's another discussion thread that has some more tips: How can I print out text messages - Apple Community

says:

"To print text messages from your iPhone, you’ll need to get the messages out of the Messages app. You can do that by taking screenshots of the conversation or copying and pasting the messages to a text app like Pages, Notes, an email etc. You can then print screenshots from Photos or print from the text app. 

To copy in the Messages app, touch and hold a message bubble, then tap Copy." 

All the best :-)