Reverse Charge Mechanism places tax liability on the recipient; requires registration and payment from electronic cash ledger. Liability to pay GST shifts to the recipient under the Reverse Charge Mechanism, while place, time and value of supply determinations remain unchanged. Persons liable under RCM must obtain compulsory registration notwithstanding turnover thresholds, except where a supplier is exempt from registration. RCM tax must be paid from the electronic cash ledger; recipients may claim ITC on tax paid under RCM only upon receipt and business use of goods or services. Suppliers cannot claim ITC on supplies where recipient is liable. Records, invoice-level return reporting, tax on advances, and self-invoicing for unregistered suppliers apply.