Question regarding shifting

I bought a 2000 Jeep XJ a while ago and due to some medical issues haven’t had much chance to enjoy her. I’ve started to take her out more and my question is what can I do with the shift lever? When I shift into reverse it barely moves the needle. Drive is in neutral. There is a big whole where the shifting covers are. Not sure what to call them. How do I fix this issue? Not sure how to post a picture.

Sounds like the linkage needs to be adjusted.