The ABN is a single identifier that non-profit organisations use to:
register for GST and claim GST credits
register for PAYG withholding
deal with investment bodies
apply to the Tax Office for endorsement as a deductible gift recipient, tax concession charity or income tax exempt fund
interact with other government departments, agencies and authorities, and
interact with the Tax Office on other taxes, such as FBT.
Your organisation’s ABN registration details become part of the Australian Business Register (ABR). The publicly available information on this register allows people to find out whether the entities they are dealing with have an ABN, are registered for GST, are endorsed charities or income tax exempt funds and/or are endorsed as deductible gift recipients.