To complete a legally binding marriage, below are the minimum documents required. Depending on the situation, some additional forms may be required. Your Celebrant will advise you.
Notice of Intended Marriage (NOIM), to be lodged at least 1 month before wedding ceremony.
Official Certificate of Marriage (2 copies)
Form 15 Certificate of Marriage (also known as 'party certificate')
As an Authorised Celebrant, I can witness and/or sign off these documents.
Other resources:
Happily ever...before and after brochure
Document outlining the obligations and consequences of marriage and stating the availability of marriage education and counselling [English version]
To be given to couples who have lodged a notice of intended marriage form with an approved marriage celebrant.
Legal (or Registered) Marriage Certificate:
Your celebrant will give you a Form 15 Certificate of Marriage (party certificate) on the day of wedding. If you need to change your name on a passport or driver licence, you need to apply for a legal (or registered) Marriage Certificate from the relevant Births, Deaths & Marriages Department of the state where you get married. Here is the information for VIC.