Addon domain setup in Cpanel is configuring another domain name to "park" on top of a subdomain of the master domain of the hosting account, and that is set pointing to a subfolder within your account. This setup allows you to have multiple domain hosting and manage all through your domain hosting control panel. For example, you can have your domain www.myinnovation.org.nz pointing to the subfolder www.mygoodbusiness.org.nz/innovation/. Please note that addon domains must be registered domain name and resolved to the server where you are setting it up as addon domain.
To setup an addon domain :
Click Addon Domains button in your website hosting account control panel.
Enter the new domain name to be setup in New Addon Domain text field.
Enter the subfolder name of which this addon domain points to in Username/directory name field. note that the setup process will also check if the specified subfolder exists in your hosting account, if not found it will be created. Also, there will be a FTP account created with this name for you to upload/download files in this subfolder
Enter a password domain in the Password field, note that this password is also the password for the FTP account mentioned above.
Click Add button and the addon domain is setup, there will be a result screen with important info after hitting the 'Add' button, please go through text in the result screen carefully before exit.