It was in the form of an invoice, clearly based on a recently filed trade mark application with IP Australia, and asked him to pay AUD$1,850 for "registration costs" to an account in Hungary.
What is it?
It's a scam. The document is obviously created as a result of the scam operator monitoring the public trade mark application register. It promises a "listing in the TM-Edition 2012". If that exists (which I doubt), it will such a worthless "thing" (because it doesn't specify if it is paper or electronic) that it is a waste of time, much less money.
Don't do business with them.