Value Added Tax (VAT) is valid tax levied by the State Government on the value added to a product or services before reaching to the final customers. Under VAT law, there are two options voluntary registration, which you can do from very first day of business and compulsory registration in case the turnover exceeds the limit which varies from state to state or the business is involved in interstate trade or business actively involved with manufacturing or even production of goods. In addition to VAT registration, assessee are also required to take Central sales tax (CST) registration if the business involves interstate trade. Under VAT / CST registration a unique TIN No. is provided to the assessee required to be mentioned at various places.