Hi i'm 20 year and 8 months and my height is 5.6 feet can i increase my height?

Growth very unlikely: An 20 yr old is not growing taller if his growth plates have fused. If not fused, he will grow a little bit (pediatrician's growth chart for him can tell if growth has stopped). To look taller, one can choose properly designed clothing & shoes, and have good posture. Vitamins, supplements, "special" foods, exercise, etc... will not make a person living in the U.S. taller (height here is genetic).