IRAP, the Information Security Registered Assessors Program, is the Australian Government scheme under which endorsed assessors evaluate systems against the Australian Government Information Security Manual (ISM). Agencies use IRAP assessment reports to decide whether a cloud service can hold government data, and at what classification level.
If you sell to or work with Australian government bodies, IRAP is the word procurement will use. For everyone else it is a useful signal of security maturity in the Australian market, sitting alongside the Essential Eight mitigation strategies and the Privacy Act on the local compliance map.