Hi! I am 20 years old girl. I am 5'4.5" tall. I want to grow atleast 2 inches more. Is it possible. If then, what should I do?

High Heels. At age 20 would not anticipate that you will grow taller. Take care.
Not possible. As my colleagues have mentioned, it is not possible for you to grow any taller. Women stop growing 2-3 years after they start having their menstrual periods. At that time the growth plates of the bones close and it is not possible to grow any taller. Your height is exactly average for American women.
Growing taller. If you already had your menses, I believe you did few years ago, no much room for growing taller, height is already genetically determined, environment and nutrition add a little, 5'4.5" is a good functional height, enjoy your life, have a healthy lifestyle, goodluck.