You technically can’t put EVs like Teslas in neutral without power. Electric cars don’t work like traditional vehicles in the sense that they just have a single gear rather than a gearbox. If you want to put a Tesla in neutral without power, you’ll have to jump-start the 12-volt battery. On some models, you can simply disengage the parking brake. Just make sure that the rear wheels roll when the tow truck is pulling the car up onto the flatbed.
This should give you enough power to get into the car. From there, hold down on the gear lever for one or two seconds and the car will go into neutral.