Credit and Debit Notes must state prescribed particulars to effect VAT tax credit or debit adjustments under the VAT rules. Credit notes and debit notes must be signed by an authorised signatory and state the selling dealer's name, address and registration certificate number; the purchaser's name, address and registration number where applicable; the reason for issuance; the serial number of the affected tax invoice; and, where tax-credit adjustment is required, the amount of variation to the tax amount shown on the tax invoice.