First, let me welcome you to iRV2, Playtyme.

We're glad to have you here.
There are hitches for light, medium & heavy duty trucks. Also different hitches are rated for towing different GVWR (Gross Vehicle Weight Rating) & pin weights of 5-rs. Some hitches are stationary in the truck bed & others are sliders, meaning they slide forward/aft on rails within the truck bed.
If you can post back with the make/model/yr of the hitch you're looking at, we could probably tell you more about it's specifics.
A couple bits of advice....
1st, don't buy the hitch 1st or you'll get locked into a specific size/weight of 5-r.
2nd, if you don't already have one, don't buy a truck before you at least narrow down your choice on a 5-r. Your truck will determine what you can tow & there's nothing like finding out the truck you just bought is underrated & won't safely tow the 5th wheel you've fallen in love with.
3rd, don't rely on the rv salesman to tell you what your truck can tow. They will tell you a Ford Ranger will tow a triple-axle 38ft 5-r just to sell you the rv.
Lori-