Well let’s see…
There’s a lot of regionalisms involved so bear with me - a native speaker might be able to tell you more than me - but it usually goes like this.
el coche = a car [often Mexico or Spain]… which used to be “stagecoach”
el carro = a car [most of Latin America] …which used to be “chariot”
el auto = a car [Cono Sur]… which I’m guessing is automóvil ”automobile / self-moving”
Then you have la guagua which is regional because some places in the Caribbean will use it as a “not a small vehicle” like “bus”… other places use la guagua to mean “baby” or “infant” because guaaaa is the sound of a baby crying.
There’s then la furgoneta which is a bigger car like a van or a station wagon, sometimes a truck.
There’s el camión which is often a very large vehicle in some places the equivalent of an 18-wheeler in some places, or a service vehicle like a lorry or those construction vehicles. In some places, it’s just a bus or big trick.
Then la camioneta which is a smaller large vehicle like a pick-up truck or a van or SUV. Usually big, but not huge.
The one constant is often el autobús or el bus which is “a bus”… though you may also see el omnibús which is also shortened to el bus.
Another constant is el tranvía which is often used as a “shuttle bus” or a kind of car that runs on a monorail or track. We would call it a “streetcar” or “a trolley” like in San Francisco.
Other regionalisms include el vagón which is taken from “wagon”… and it often means “a carriage”, a different word for la diligencia ”a stagecoach”. In modern terms, el vagón is sort of like “Volkswagen” [“People’s wagon”]. Though you then see la vagoneta meaning “small wagon” which are also sometimes used for trams or shuttles. These two are used often in a “train car” kind of way.
There are some countries that will use English loanwords; el jeep, el pick-up, el van, el minivan
Some will use sort of approximations; el vehículo deportivo ”sports car”, or el todoterreno ”SUV / all-terrain vehicle”
There’s a lot of regionalism involved, but a lot of countries are used to each other’s regionalisms at least in some way so if you say camión instead of camioneta they might mistake what size to expect, but they’ll know it’s a vehicle of some kind. Chances are they won’t have zero idea what you’re talking about.