What should I take to gain muscle and or weight? I am a girl of that matters who is skinny?

Gaining muscles is better than gaining fat. But girls tend to have fat even if they work out. So start by doing body weight exercises to burn fat and gain muscles. Push ups burn fat and build all upper body muscles, where its doesn't make it all swollen but lean. Sit ups burn stomach fat while running also can burn fat which makes the chubbiness or fat in the stomach go away and we all know having 6 packs are better. Squats build legs and jump rope builds legs so those are both well for cardio except jump ropes should be done less because it can be bad on the calves. If you want to learn more just check up muscle anatomy, exercise and training, create a diet based on your health, medical restrictions and people choices. Lastly create the ultimate workout. Ask different questions to gain the most knowledge. Something you should remember in exercising is technique, motivation, physical limit and self benefit.