I am too thin and weak. should i join gym? and what kind of machines i must use in beginning?

Training partner.: If you don't have any medical condition that restricts you from exercise. Start an exercise program combination of cardio and weightlifting. Enroll a family member or friend as a training partner .If you can afford hire a personal trainer. Always start with moderate intensity program like walking , swimming and lifting lighter weights. Use the machines instead of free weights to avoid injury.