Well I thought I could look online and find a nice explanation with drawings and such. But didn't find any after a short search.
OK a standard hitch works on 95% or more of modern trucks and trailers. Slider hitches actually let the head slide on rails--side to side. That is useful for older trailers that do not have a rounded front end and for short bed trucks. A standard hitch head is fixed and does not side around tho it will swivel.
So unless you are getting a fairly old rv then a standard hitch is probably all you need. Even with new RVs some people like sliders with a short bed truck but most seem to feel that you are fine without one if you are careful.
Unless you are getting a new truck and get it with 'hitch prep', which you should, then you'll have to get rails installed under the truck bed to attach the hitch to. If you have a prep package then you need to buy a hitch designed to use that setup.
I never had rails installed but I think the rails plus installation should run in the $200 range plus/minus. Rails can leave the bed of your truck obstructed when the hitch is removed. The prep packages leave a nice flat bed.
Be warned that these hitches weigh around 200 pounds, sliders more. Look on etrailers.com for more info.
Arctic Fox 25Y Travel Trailer
2018 RAM 2500 6.7L 4WD shortbed
Straightline dual cam hitch
400W Solar with Victron controller
Superbumper