The first character of the WDD code represents the country of origin. In this case, "W" stands for Germany. The second character represents the manufacturer. "D" stands for Daimler AG, the parent company of Mercedes-Benz. The third character represents the vehicle type. "D" stands for a passenger car.
So, a VIN number that starts with WDD indicates that the vehicle is a passenger car manufactured by Daimler AG in Germany.