In case of Reverse Charge Mechanism (RCM), a person should issue an invoice to oneself also called ‘self-invoice’. If a person is liable to pay GST under RCM, he should self-invoice. At the time of receipt of goods or services or both by the person liable to pay GST under RCM, he should issue an invoice at the time of such receipt. Moreover, at the time of making payment to the supplier, he should issue a payment voucher.