How can I condense the display categories on an all pages   

@alsharif
"How..." is not question for support.
Please specify your question, what you did and what you need.

I need to reduce the space given to the display of categories

You can reduce size of icons, remove title, reduce padding,...

Thank you! Which file(s) I need to edit and the code to do just that.

@alsharif
You can add to theme style.css following (at first line):
#top-cat h1 {display:none!important;}
#top-cat {padding-top:15px!important;}
#top-cat ul li {margin-bottom:5px!important;}


Many thanks frosticek for the great support that you provide.  Works like a charm. Resolved.