Assuming you would like to know how to properly immobilize a vehicle:
There are a few ways that you can immobilize your car. The most common way is to use a wheel clamp. This is a device that fits over one of the wheels and prevents it from turning. There are also boot clamps, which fit over the entire tire and prevent it from moving. Both of these devices can be purchased at most auto supply stores.
Another way to immobilize your car is to remove the battery. This will prevent the engine from starting, but it will also disable any electronic locks or alarms that might be installed on the vehicle. If you do this, be sure to store the battery in a safe place where it cannot be tampered with or stolen.
You can also remove vital parts of the engine, such as the distributor cap or spark plugs. Without these parts, the engine will not be able to run even if someone tries to start it. Of course, this will require some knowledge of car engines and should only be attempted if you are confident in your abilities.
The best way to immobilize your car is actually to have an anti-theft device installed by a professional. This could be something as simple as a steering wheel lock or an alarm system. These devices will deter thieves from trying to steal your car in the first place and will make it much easier for you to track down your vehicle if it does happen to get stolen