What is the difference between a deed and an agreement?
An agreement between two or more parties generally requires valuable consideration (e.g., money, or property) to be provided by each of the parties to be legally enforceable.
However, a document executed as a deed can be enforceable, even if one or more of the parties to the deed do not provide valuable consideration.
To be a deed, the document needs to state that it is a deed, and it needs to be executed by stating that it is being "Signed, Sealed and Delivered" by any individual parties (although the requirements for the execution of a document by a company are contained in the Corporations Act 2001, and the company's own constitution). This is a technical requirement, and a throwback to when people actually need to affix their "seal" to a deed to make it valid. Even though seals are not now required, the deed still needs to state that it has been sealed.
Also, all signatures on deeds by individuals generally need to be witnessed by an independent adult.