Iwant to increase body weight which exercise should i do?

Muscle building: Seek exercises that stimulate the large muscle groups including thighs, back and chest. By performing intensely for short periods of time on a regular basis, your body will build muscle. Muscle weighs more than fat, so feed your muscles with dense nutrient foods and get rid of the concentrated sweets, bad fats and soft drinks. A personal trainer would be a great resource for you.