A person making taxable supply of goods or services or both and if his turnover cross 20 lakhs in a financial year, he has to compulsory register under GST within 30 days. The limit in special states is 10 lakhs.
However, if a person makes supplies in the course of interstate trade he has to be registered under GST.
Person who is required to pay tax under Reverse charge has to get himself registered.
E-commerce operators liable to collect tax source have to compulsory get registered. Person selling goods online on these portals has to obtain registration.
Aggregator service providers have to obtain registration.