Hi Neha,
To lose weight from the stomach, you need to lose weight from overall body because abdomen is one of the commonest site for excess fat deposition. Start working on reducing the total body fat content, you will automatically see changes in your abdominal area. I will suggest you to do aerobic exercises like walking, jogging, running, cycling, skipping, step aerobics, swimming, dancing etc. Also add some abdominal toning exercises like crunches, planks, swiss ball workout etc. Take care of diet also consume low caloric diet. Try to be active instead of being sedentary because, sedentary lifestyle is one of the biggest cause of obesity in past few years.