As long as you do not have the Startup Plan, you can follow the instructions below to add an additional domain(s) to your hosting package:
1. Log into your Name.com account and click the "Account" button at the top of the screen. Then click the 'My Web Hosting" link to the left.
2. Click "Hosting Dashboard" button in the upper right of the page
3. From your cPanel, scroll down to the "Domains" section and click "Addon Domains"
4. Type the domain in the domain, Subdomain/FTP Username, Document Root (usually public_html/domain.com), and password/confirm password.
Once this is done, go back to the "Hosting Services" page of the Name.com account and click the 'Sync Addons' button. The select the domain(s) you are trying to add from the drop down list. Once you see the Addon domain DNS records (there will be no records), click the "Hosting Defaults" button below. Doing this will add the necessary DNS records and the domain(s) should be resolving properly to your web site(s) within 24 hours (assuming you have content uploaded to the server). If you also wish to use the hosting account for email, you will need to apply the Standard Email template to add the necessary MX record in your DNS.