To set up an efficient business in India GST is a must. As per Indian Government tax rules and Regulations, every merchant located in India is liable to pay the GST amount for the sales of goods. Magento 2 GST module helps the Magento 2 store to support the GST functionality as per norms set under the Indian Government tax rules and Regulations. 

https://webkul.com/blog/magento2-ecommerce-gst-plugin/