If you registered your Domain Name with us
► Login to our website
► click Domains->My Domains
► click Manage button for the domain
► click Get EPP Code in left menu
If you registered your Domain Name with another company
Login to the website where you bought the domain from. Then look for the option for the EPP code or Domain Password or Authorisation code.
Another option for au domains
For au domains you can also have the password sent to the current domain contact email address. Go to the auDA.org.au site, enter your domain and name and recover the password.