I am 18 years old and I am having only 136.5cms hieght. I am short compared to my friends of same age. Will I grow taller more? How can I grow tall?

A doctor can check. A doctor can check, because 54" is short. There is little or no growth in boys at age 18 years. Most people reach their maximum height in their late teens. Without nutritional problems or chronic childhood illnesses, height is largely based on genetics and parental heights. Aside from eating right, exercising, sleeping well, and being happy, there's not much a person nor his doctor can do.