I'm underweight and need to put on and gain much weight. Does exercices like jump rope that I practise can lead to lose more weight as it is said?

Weight Gain. You are more likely to gain weight through weight training three times a week than aerobic exercise, although jumping rope is great for fitness but try to accent weight training until you gain sufficient weight. Also consult with a nutritionist to help design a food plan that will also help you. Check with your doctor to make sure no medical issues are causing your problem. Best wishes.