If you registered your Domain Name with us
► Login to our website
► click My Domains
► click Active (or spanner icon)
► click Get EPP Code
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 to the current domain contact email address. Go to the auda site, enter your domain and name and recover the password.