If you need to make a statutory declaration for placement, to apply for special consideration, or any other reason you can find the most current rules and advice on the Stat Dec page of the State Government Justice and Community Safety website. See: Stat Decs on justice.vic.gov
See also: What is externally verifiable evidence?
For specific information and a template to get a stat dec to update the status of your police check (e.g. for placement) see also: Police checks and Statutory Declarations