GST registration is the step that gives a business a GSTIN. You need it if your turnover crosses the threshold for goods or services, and also in some cases before that — inter-state supplies, selling through an e-commerce operator, or a voluntary registration because a customer will not buy without it.
The threshold is not one number for everyone. Goods and services differ, and special category states have lower limits. A person who only makes exempt supplies may not need a GSTIN even at a higher turnover. That is why Digital Filings asks what you sell before quoting a filing.
A normal application needs PAN, Aadhaar of the authorised person, photographs, proof that you possess the place of business, and bank proof. Companies and LLPs add their incorporation papers and usually sign with a DSC. Proprietors often finish with Aadhaar authentication.
After filing you receive an ARN. If the officer has no query, registration is commonly issued within a few working days. A query pauses the clock until you reply. Skipping the reply can get the application rejected, and you then start again.
There is no government fee for a standard GSTIN. Budget time and a professional fee, not a stamp duty. Once the certificate arrives, returns start — even a nil month has to be filed.