GSTIN stands for Goods and Services Tax Identification Number in India. It is registration number of a person who have registered in GST. Registration is mandatory in many cases. e.g. When a person crosses the Threshold limit of Turnover. If a person makes an inter-state supply of goods. In case of CTP, NRTP, ISD, E-commerce portal liable to deduct TCN in India. They all are liable for registration and to take GSTIN. It is made by the PAN And the state code digits. The configuration of a GSTIN is like this.