StableHost offers unlimited additional domains for your account (on most of our hosting plans), as long as they are your own domains.
Log into cPanel.
Click on Addon Domains, under the Domains section.
Once you get in, enter in the domain in the New Domain Name section.
Then click The Subdomain field and the Document Root (usually public_html/domain.com) will automatically fill in.
If you wish to create an FTP account for your addon domain name, check the option Create an FTP account associated with this Addon Domain.
FTP Username: will be filled in automatically
Password: password for the associated FTP account
Password (Again): repeat the password
Click Add Domain.
* The Web Hosting Starter Plan does not support additional domains.