Even though your wedding ceremony can be completely personalised to your wishes, legal requriements to marry in Australia state your wedding vows must comply with section 45 of the Marriage Act 1961.
You must say these following words as your marriage vows:
"I call upon the persons here present to witness that I (Bride or Groom) take you (Bride or Groom) to be my lawful wedded wife (or husband).
After these words, you may write your own vows or choose other meaningful words that are important to you.