If you looked up the announcement on ASX, you wouldn't see the...

If you looked up the announcement on ASX, you wouldn't see the VAC, but if you got the email or letter, than it should include it.

I think it's not HIN but a unique code generated for you - 'Voting Access Code'.

From the email:

Account Name: MR ##### #### ######
STEP 1: Visit https://www.votingonline.com.au/crowdmobileagm2018
STEP 2: Enter your Postcode (if within Australia) OR Country of Residence (if outside Australia)
STEP 3: Enter your Voting Access Code (VAC) - ######
STEP 4: Follow the prompts to vote on each resolution