The first step is to obtain your marriage certificate once you register the marriage form. You then need to get an affidavit (stamp paper) for changing your name, detailing the reasons for the name change, your old and your new name. Once that's done, you need to then declare your new name through local newspapers or the Gazette of India. Although, because formalities change from state to state, we advise you to contact your local government authorities for more information.