Australia Digital Passenger Declaration is an app that you need to fill out within three days before your departure to the said country. In this declaration, you would have to state your flight details, contact details, and health status. You also need to provide details of your quarantine and COVID-19 vaccination proof.

This safety protocol is to prevent the spread of Coronavirus and for the well-being of the citizens of Australia. If you happen to test positive for the virus, it's easy for the Government to contact you. This way, they will be able to provide you with the utmost care for you to recover.