On the left hand side of your screen there should be a UI element which you can open up by pressing the arrow, then hit the “i”.
You should be able to enable pet unit frames for party members here.
Edit: spelling issues and you have to be in party to see it, otherwise go to interface options and search there, i don’t know for sure what the tab is called.
Unfortunately i haven’t really paid attention to it yet, i just enabled the raid style frames because i like the resizing and move options without having to install an addon for it.