Car fires don’t happen frequently, but when they do, they’re a potentially deadly emergency. According to figures from the National Fire Prevention Association, fire fighters responded to more than 200,000 car fires in 2010—and car fires killed 285 people that same year.  
Knowing what to do can help prevent injuries or even save someone’s life.
Act fast when a fire breaks out
If you smell smoke or see flames coming from your car while you’re driving, it’s important to remain calm—but act quickly.
Recognize that car fires can break out in places other than the engine compartment. They also can occur under the vehicle, near the wheels and brakes, in your dashboard, and even inside the car. In fact, interior fires can be among the most frightening because of your close proximity to the flames, fumes, and smoke.
The National Safety Council recommends following these steps if you’re driving and a fire starts:

Signal, and immediately move to the closest safe place to stop, whether that’s a side lane or a median.
Stop the car and turn off the ignition.
Get every person out of the car, and don’t allow anyone to go back to retrieve personal items. 
Move far from the burning vehicle to avoid the flames and toxic fumes—at least 100 feet—and also keep bystanders back.
Call 911.
Alert oncoming traffic if possible.

It’s generally not recommended that you try to put out the fire yourself. Opening the hood or car doors increases the air supply and may accelerate the fire.
Once the fire has been put out, contact your insurance agent. If possible, take photos of the damage, and collect the names and phone numbers of witnesses. Ask the firefighters when and if it is safe to remove personal items from the vehicle. Have it towed to a repair shop for an inspection before attempting to operate it again.
Ways to help prevent vehicle fires
While some car fires occur in collisions, they are more often caused by problems with a vehicle’s electrical or fuel system. Your best line of defense is to have these systems checked out at every service call. In between times, look for these potential warning signs:

1) Fuses that blow repeatedly
2) Spilled oil under the hood left over from an oil change
3) Oil or other fluid leaks under the vehicle
4) Cracked or loose wiring, or wiring with exposed metal
5) Very loud sounds from the exhaust system
6) Rapid changes in fuel level, oil levels, or engine temperature
7) A missing cap from the oil filler
8 Broken or loose hoses

https://learningcenter.statefarm.com/auto/safety/what-to-do-if-your-car-catches-fire/