Debit note in GST allows suppliers to raise taxable value and adjust tax liability through returns. Debit notes under the GST regime enable a supplier to increase the taxable value or tax charged on an earlier tax invoice when the original invoice understates value or tax; such debit notes must be declared in the return for the month of issue, are treated like tax invoices for return and payment purposes, and must contain prescribed particulars including supplier and recipient details, unique serial number, reference to the original invoice, taxable value, tax rate and amount, with records retained for seventy-two months and accessible at relevant places of business.