The Tow Truck is a gamepass you can buy.
The gamepass costs 100 Robux and when you buy it, you can become on or off duty.
When you are on duty, open up the phone and open the Vehicles app. Click on the utility cars section (picture of bus) and select the Tow Truck to spawn the tow truck. Drive around the city to find old, empty, destroyed, and rusty cars to tow back to the impound. You have 120 seconds to tow the car to the impound or else you wouldn't get paid. The more time you take, the less money you will earn. You can get paid up to 15,200 dollars for each car you tow.
To tow a car, hop out of the car and click the hook on the back. Drag the hook onto the back of another car.