My age is 20 and my weight is 34 kg how can i increase my wieght?

See Dr., then eat...: If one is truly underweight (based on height, family background, and body type), a Dr. can evaluate for a hormonal, digestive, or other disorder. If no medical cause is found, then one can add weight by eating more calories of nutritious foods, while also doing weight-training to increase muscle. Proteins: egg white, chicken breast, salmon,... Better fats: olive oil, peanuts, almonds, tofu,....

Eat healthy high: calorie foods. Eat 6 meals/day. Work on strength training to build large muscle groups. Workout w heavier weights w fewer repetitions. Sleep at least 8 to 9 hrs/night. Hydrate well w water. Foods to help w healthy weight gain: almonds, cashews, pecans, sunflower seeds, flax seeds, walnuts, hummus, Avocados, granola, trail mix, dried fruits, extra virgin olive oil, canola oil, protein shakes, >