Dear Ashhar, this answer is being written assuming that CS stands for Compaylny Secretary. There are 3 stages in a Company Secretary course namely Foundation, Executive amd Professional. If you want to become a CS you should complete all these 3 levels. If you plan on joining the course right after your 10+2, you should complete all these 3 stages and if you want to study after graduation it is just Executive and Professional levels. You need to complete 15 month practical training as a part of your CS course. A candidate is declared to have passed the Foundation / Executive / Professional examination if he/she secures at one sitting a minimum of 40% marks in each paper and 50% marks in the aggregate of all subjects.