Under the Australian Corporations Law, every company in Australia has been issued with an Australian Company Number (ACN), which must be shown on a range of documents. The purpose of the ACN is to ensure adequate identification of companies when transacting business. Non-Australian entities can ignore this field Australian business entities or entities carrying on a business in Australia who are registered for the goods and services tax (GST), will be assigned an ABN (Australian Business number) for taxation purposes in respect of GST charged and paid.