Section 31, The Goods and Services Tax Act, 2009

(1) A GST registered supplier who makes taxable suppliesis required, at the time of the supply, to issue the recipient with an original GST invoice, for the supply. (2) A GST invoice and a sales receipt shall contain the prescribed information. (3) During the first 12 months of the GST becoming chargeable under this Act, the GST invoice issued by the registered person shall be the one printed by the National Revenue Authority for the use of the registered person unless the registered person is authorised by the Commissioner-General in writing to print its own GST invoice containing the prescrided information .