In Victoria, there are two key documents involved in the purchase of a property
1) Vendor Statement and
2) Contract of Sale.
A vendor statement must be provided by the seller prior to any constract being signed and should inlcude all disclosures about the property. This is a legal requirement in all States of Australia and is not optional. Be certain you receive it and confirm in writing that it contains all relevant information about the property. Compare it to the Inspection Report (if you get a professional inspection done).
The contract of sale will contain the final conditions of sale, price and settlement period.
It is strongly recommended that you employ a conveyancor or solicitor to guide you through the process and ensure all of the necessary documentation is in order.