Reverse charge mechanism requires recipients to self-invoice, comply with time limits, and issue payment vouchers upon payment. Reverse charge liability requires the recipient to self-issue GST-compliant invoices when goods or services are procured from an unregistered supplier and the supply falls under the Reverse Charge Mechanism. The recipient must indicate reverse charge status on invoices, comply with statutory time limits for issuing such invoices from the date of receipt, and issue a payment voucher when making payment to the unregistered supplier, in accordance with the CGST invoicing rules.