If someone else has decided to use your property as a parking lot and you want to have their vehicle removed here are your options. Doing it yourself is likely not the best option as you may find yourself in some dubious legal trouble.
The first step is always to call the police. The car may be considered trespassing and in that case the police can issue a citation and possibly have the car towed at no cost to you. This creates an official paper trail and is the best bet for both you and the owner of the car.
The police will also check to see if the vehicle is stolen and create a report accordingly. If the vehicle is not stolen then it is up to you to find a reputable towing and wrecker service of your choosing. Most every wrecker service will be willing to remove the vehicle form your property at no cost to you. They will then file the proper paperwork with the police department so the registered owner will know where their property is.
The bottom line, don’t ever try to move the vehicle yourself as you will be held liable for any damages that may occur. Worst yet if the vehicle is stolen you could find yourself in some hot water, through no fault of your own! Leave this to the professionals at your local police department and towing companies.