Am 25 and I have 50kg. Am male and need to increase my weight to 65kg
basicly mate you need to over haul your calorie intake the norm is about 2500 increase to 3000 3500 per day it might seem a lot. but instead of 3 meals per day and snacks and stuff eat 6 sit down meals a day even if there small.and yep like the comment above hit the gym overhauling your calorie intake will make you put on weight and through high protien shakes that fat will become muscle in no time.
Eat more, put a little weight on then Work out .. turn it into muscle .. muscle weighs more than fat.