Unless you used your car for your self-employment business, you don't report it on your tax return at all. If this was a business use vehicle follow the directions below to report the loss.
As of 2017, you can't deduct a personal loss unless it occurred as part of a federally declared disaster.
If it was a business use vehicle, you can claim part of your loss as part of your itemized deductions. If your itemized deductions are not more than your standard deduction, it won't affect your taxes.
This is how to enter a loss on your business use vehicle: