eHealth services like the national eReferrals service have played an essential role in the fight against COVID-19. Such services are built on a foundation of healthcare interoperability standards, which allow the clinicians, labs, hospitals, pharmacies and patients involved to share data appropriately, regardless of the system they are using. Internationally, healthcare interoperability standards have been in use for several decades. Over the last 10 years, HIQA has published a range of national standards, recommendations, and guidance to provide strategic support for healthcare interoperability in Ireland. This document answers frequently asked questions about that programme of work — from an overview of key eHealth concepts to the international context for healthcare interoperability to the national standards, recommendations, and guidance supporting the eHealth services that have proven so essential in the management of COVID-19.