Yes, it is possible to host more than one domain on your account. You can do so right from cPanel. Find out more in our Create a Subdomain, Parked Domain or Add-on Domain article.
For hosting multiple domains that go to the same site, use the Park Domain feature.
For hosting multiple domains that go to separate sites, use the Add-On Domain feature.
To make a subdomain (IE: http://subdomain.yoursite.com), use the subdomain feature as outlined below.
Create a New SubDomain
Log in to your cPanel account and click Subdomains
Enter a new sub-domain, like 'sub.example.com'
cPanel will create a DNS entry (an A record) for that subdomain pointing to your IP address.
Subdomains and add-on domains will each be given their own folder. This folder will contain all the files for that name.
Note: although you can host multiple sites/domains, all of them will have the same log in name and password. If you want the ability to separate accounts entirely, it's necessary to have a Reseller account. Contact firstname.lastname@example.org to upgrade.