I'm assuming you mean WW2, seeing as WW1 germany wouldn't have been able to launch a successful invasion anywhere besides France.
If Germany defeated U.S. during WW2, Japan would have had to destroyed our naval fleet. Most likely, the U.S. and it's territories (Guam, Phillipines, Puerto Rico) would be split up between Japan and Germany. Possibly some new countries would be created between the two as "buffer states" seeing as they both believed in themselves as aryan, which would have led to a war between the two.
