TCS is one of our Platinum partner and it has a Pega practice. As you are working with TCS you have got free access to all the Self Study courses in Pega Academy. Please go through them. To start with you can go through System Architect Essential Part I followed by System Architect Essential Part II.
It is not mandatory to undergo SAE I and II course to write the exam, but yes in order to appear for the exam you need the knowledge being taught within these two courses. IF you are working for one of our customer and you have thorough knowledge of Pega 7 then you can appear the CSA exam in any Pearson vue testing center.