GST registration is required when aggregate turnover crosses the notified threshold, when a person makes inter-State taxable supplies in specified cases, or when registration is compulsory under the Act for other notified reasons. The application collects constitution of business, PAN, promoters, principal and additional places of business, bank account, and the nature of goods or services supplied.
Before filing, the place-of-business documents, constitution papers, and authorisation are checked against the details that will appear on the GSTIN. After the registration is granted, the same details must be kept current. Amendments for change of address, additional place, authorised signatory, or bank account are filed so that e-way bills, e-invoices, and notices reach the correct location.
Composition levy, where eligible, is a separate election with its own return form and restrictions on input tax credit and inter-State supply. Opting in or out is timed to the dates prescribed in the rules. Cancellation or surrender, when the business closes or falls below the requirement, follows the return and payment position up to the date of cancellation.
A registration file that stores the ARN, GSTIN certificate, and every amendment order is the reference used later for returns, refunds, and departmental correspondence.