Depends on the hitch. Andersen and Recurve hitches don't require ball grease as the hitch ball moves with the tongue.
Someone makes hitch grease which is what I carried because it came in a small plastic container. I don't think the grease was anything special. After ruining a couple of pairs of pants, I used a foam hitch ball cover when not towing which worked well.
Don't grease points where the hitch relies on friction for anti-sway properties. My Reese had friction pads similar to brake material.