Your tow vehicle has several ratings that are inter-related.
Max tow rating is what the vehicle is rated to pull, under prime conditions. Those conditions DO NOT include aftermarket accessories, passengers, pets, or cargo of any kind. As you add weight (people, pets, accessories, cargo) to the tow vehicle, you are reducing it's max tow capacity, along with it's available payload, pound for pound.
Payload (AKA cargo carrying capacity) is what the vehicle is rated to carry. Payload is used up by weight of people, pets, cargo, accessories, weight distributing hitch, and tongue weight from the trailer. Should be a tire / loading sticker on your drivers door post. It will show your payload / cargo carrying capacity. It is possible to exceed payload before you get close to that max tow weight.
You also have weight ratings on the hitch, axles, and tires. Your true "max tow weight" is limited to the weakest link in your overall ratings. Normally, that is payload.
Here's a
link to a calculator that may give you an idea of what is a good weight for you to tow.