Well aside from a passport, you need a visa that gives you the right to work and live there, and getting that takes a lot of effort, and money as it turns out. For Aus, a good place to start is to check if your profession is on their skilled occupation list
https://www.immi.gov.au/Work/Pages/s...lists/sol.aspx , if it is, you can maybe get in on the general skilled migration program. That's what I'm trying.
You'll also need unabridged birth certificates (and marriage certificate if you're married) for the family, a police clearance certificate, a good CV with references, and documentation for whatever certifications or higher education you have, and you'll have to do an IELTS test to prove that you can speak English proficiently.
If you go through an agent, they will help you through all that and do all the dealing with immigration for you.