Some description is provided here but admittedly not specifically UTM: Go To XY—ArcGIS Pro | ArcGIS Desktop
But one trick to help answer your question about UTM format is given here "When a new unit format is chosen, coordinates in the recent history list are converted to match the new format."
So if I've found a location in DD, when I switch to UTM, I get my previous entry converted:
Another trick in terms of understanding format is to right-click on the map (with the Explore tool active) > Convert Coordinates > UTM
You'll get something like this: 31N 467138 0049824