You need to take high protein diet. Ask me directly for customized diet plan for you

Hi welcome - you need High carbohydrate enriched by high protein around 25- 30℅ total calories Inclusive dietary fat to gain weight at least 55 kg. So far ,I can see you are severely malnourished girl.you need immediate care about protien. Good metabolism required even to get digestion of carbs like rice, roti, etc with dairy foods , fruits like Banana, citrus, all , 400 GM per day green vegetables within sabji,. Sleep more at least 8 hours. Add soup, veg, non veg chicken stew etc. I can also advise to buy Ensure plus & have two to three times with some water or preferably milk. Dal, sprouts, nuts, some dry fruits , peanut butter, butter.milk, juices, curd ,are very helpful. Home based khchdi, Dalia, poha, Biriyani, fried rice, polao are good by  to plan high protein diet, so that immediately can come up 15-20 KGS although it should be achieved gradually.