GST registration is mandatory for businesses with turnover exceeding ₹40 lakhs (₹20 lakhs for northeastern states). This guide covers everything from eligibility criteria to the complete registration process. We'll explain the different types of GST registration, required documents, and step-by-step online application process. Key documents include PAN card, Aadhaar card, business registration certificate, and bank account details. The process involves filling Form GST REG-01, uploading documents, and verification by tax authorities.