The following documents describe the features located in the cPanel Domains box.

Recommended reading: Full cPanel guide for webmasters

• Subdomains — This area of cPanel allows you to create and manage subdomains.
  Subdomains prefix to your domain name and point to a subdirectory within your public_html folder.

• Add-on Domains — These features pertain to add-on domains. Some hosts do not allow cPanel users to have add-on domains.

• Parked Domains — This area of cPanel allows you to create and manage parked domains. Parked domains function as pointing devices.

• Redirects — These features allow you to create and manage domain redirection.

• Simple DNS Zone Editor — This screen lets you add and remove A and CNAME DNS records.

• Advanced DNS Zone Editor — This screen lets you add, edit, and remove A, CNAME, and TXT DNS records.

Source: http://docs.cpanel.net/