Let’s use the Addon Domain feature to add another domain name to this account by clicking on the Addon domains link.
Enter the new domain name and the directory name in your main account where this new domain will be pointing.
Then enter a password for this new addon domain
Re-enter the password again and then click on Add Domain button
Then Go Back to home icon and select the FTP accounts link, scroll down. There is an FTP account automatically created for the new Addon Domain demo123.com.