Rule 88 of the CGST Act – Identification number for each transaction.-
(1) A unique identification number shall be generated at the common portal for each debit or credit to the electronic cash or credit ledger, as the case may be.
(2) The unique identification number relating to discharge of any liability shall be indicated in the corresponding entry in the electronic liability register.
(3) A unique identification number shall be generated at the common portal for each credit in the electronic liability register for reasons other than those covered under subrule (2).