Plesk user accounts hierarchy is limited to four user levels:
For your customers who need to resell hosting services or host numerous domains/web sites, you will create client accounts.
Note: for the purpose of hosting your own sites, you should use a special service account which is created during Plesk setup. The account is registered with the control panel under the name My Domains.
Customers with access to client accounts can host on the server any number of sites you allow. They can host the sites of their own and/or resell hosting services to other users: for that purpose your resellers can create domain administrator accounts for their own customers.
Customers with access to domain administrator accounts cannot resell Web hosting services or host more than one site on their hosting accounts. They can only manage their own sites. In the current implementation of Plesk control panel, domain administrator accounts can be created only after the respective domains (web sites) are hosted on the server.
All site owners can set up e-mail accounts for themselves and provide other users with mail hosting services: for that purpose, they create e-mail user accounts and grant e-mail users with access to control panel.
Site owners can also host personal web pages or small sites for other users under their domains. However, the owners of such sites usually do not have their own domain names and cannot have a dedicated control panel environment.
All permissions for operations performed in the control panel you define for a reseller (client account) allow the reseller to further assign them to his or her customers. The resource allotments you define for a reseller can be further redistributed among reseller's customers. For a full list of permissions and resource usage limits you can define, refer to the Managing User Accounts section.
All quotas you define for a client or domain administrator's account are soft quotas: the control panel indicates resource overage by showing the respective icons in the control panel, sends notices by e-mail to the respective users, but it does not automatically suspend user accounts or Web sites.
The control panel does not have a built-in billing system, therefore, we recommend that you use a third-party solution of your choice, or use Plesk together with Parallels Business Automation solution.