Debit note in GST creates additional tax liability and must be issued with prescribed invoice particulars for proper compliance. A debit note (including a supplementary invoice) must be issued when a tax invoice understates taxable value, tax charged, quantity or applicable rate; it must contain prescribed particulars including supplier and recipient details, unique serial number, date, reference to the original invoice, enhanced taxable value, rate and tax amount, and signature. Issuance creates additional tax liability and is treated like a tax invoice for returns and payment. Records must be retained for seventy-two months from the annual return due date and be accessible at registered business locations.