Your vehicles are under Menu → Vehicles & Equipment. Tap Add new vehicle to register one, or tap a vehicle you already have to update its photos or insurance. You can keep more than one on your profile, and an offer matches whichever of them fits the route.
Businesses on Metrobi post jobs for three vehicle types: SUV, minivan and cargo van. Each vehicle carries a status: Processing while photos are in review, Verified when it can take jobs, Update needed when something was rejected, with the reason on the line below.
Removing a vehicle works only when it is turned off and you still have another active one. On a vehicle that is already disabled, Remove vehicle shows at the bottom of its page. A vehicle that is still active has to be turned off first, and support can do that for you, so send them the make, model and which vehicle to keep. A profile needs at least one vehicle, so the last one cannot be removed.