Am I too thin how do I get fat?

Doctor, I'm too skinny. I am 1.69 in height and I am weighing 56 kilos, but I find myself very thin. My legs are long and thin. How do I get fat, as a right and a lot, but not fat. Is there any medicine, vitamin that increases my appetite and makes me fat? Thank you
Expert answer:

I find it hard to find something that really makes you gain weight as you would like; Physical exercises can help you by increasing muscle mass and consequently weight. Continue to eat well, preferably healthy foods. Usually thin women like you only gain a little weight after the first child (may not be a viable option for you now).