how to design head light of a car using solid works
Headlights come in all shapes and sizes. You didn't specify a shape so I will generalize. A round headlight with a domed back will be easily done with revolves for the dish shaped back as a part and a revolved shape for the lens part. You will need a retainer ring to hold the lens to the back so that will be another revolved part or and extrude thin. with a secondary cut in back to make room for the lens.
Most of the techniques are basic skills and a round headlight is easy and a good place to start. An elliptical in fender light would be best done with surfaces and is an intermediate level of skills. Visualize the individual prts and create them then create an assembly to build the final product.