<h1>GST registration requirement: businesses must register by the deadline or forfeit input tax credit and face penalties.</h1> Businesses making taxable supplies must obtain GST registration where turnover exceeds the statutory threshold and register in every state/UT of supply; those below the turnover threshold or exclusively dealing in exempt supplies need not register. Migrated taxpayers with provisional IDs must complete registration to receive GSTIN, new taxpayers must register by the general deadline, and businesses crossing the threshold during the year must apply within thirty days. Registration permits passage of input tax credit; non-registration when liable denies that credit to purchasers and attracts penalties. Online registration is available via the common GST portal using PAN, email and mobile.