Documents from the Department of Immigration and Training have different methods of being verified.

Confirmation of Enrolment CoE can only be verfied by calling up the institution that issued the CoE. The CoE should have contact details to call the institution.

An Immi Grant can be verified by going to https://online.immi.gov.au/evo/firstParty?actionType=query
The Immi Grant will have the passport number and other details the website will ask for to verify the Immi Grant.