I hear if follow 1200 calorie i shouldnot exerise as it is very low calorie and if i want to exercise try 1500 calorie is that true i try lose weight?

Need more info: It is important to both exercise and control calories. 1200 calories is not too low to avoid exercise. Depending on your height and weight, it may be more than enough. If your BMI falls to 18, then it would be a concern.

Not true : Weight management is complex and has multiple factors including level of activities, mental health, adequate sleep and medications. Generally most people will do well if the consume between 900 and 1500 calories daily depending on their energy needs with 4 to 5 days of moderate exercise