Hi Will. Welcome to the CEG!
A CarFax is a vehicle history report. You run a VIN number through CarFax and it tells you if the car has been in any accident, has been flood damaged, has a salvage title, was a lease/rental vehicle, checks for odometer roll backs and other issues that you want to be aware of before you buy a vehicle.
You have to pay to run a VIN number.
Here is the link with the information:
CarFax
