Tidy Plates is a great addon for PVP. If you press Ctrl+V while in game, you will notice some hp bars appearing above players, mobs, etc. To turn that option off, press Ctrl+V again.
Tidy Plates is modifying that hp bar adding more options like the bar will start to have different colors depending on classes, pink for paladins, green for hunter, etc, it can display a small icon with the class, display their hp in percents.
Here are the settings, you can try to modify them further:
Primary theme, secondary theme stands for your specs > primary spec – secondary spec (dual specs)
These settings are for the second theme > neon damage that I’ve found to have the best looks.
This is what you need to have at names (interface options):
(notice that you can reset the options here to default with no issues, reset only for the name section)
Tidy Plates Neon Damage settings:
About the range issue
Tidy Plates cannot display the bars on target that are further than 20 yards because the game isn’t allowing this.
To disable / enable Tidy Plates just use control + v, once for turning it on, and another time to turn it off.