Reseller hosting usually provides a central management interface for adding end user web hosting accounts. The leading standard for web hosting control panels is cpanel/whm software. Cpanel software is a web based control panel software that allows users to manage all aspects of their website hosting account. (Including domain management, email account management, stats management and many other tools for web hosting management.).
Cpanel software comes with a specific interface for resellers called WHM aka web host manager. The whm interface allows users to manage, add, remove and modify end user cpanel accounts mainly for reselling purposes. The whm interface also allows hosting package creation / modification and feature management for enabling and disabling of end user cpanel applications or modules.
The WHM interface is usually a preferred platform to resell hosting accounts and is currently the most widely used application for reseller hosting.
You can read more about cpanel/whm software here.