From Agents > Agent Profiles you can select what access an Agent has across the helpdesk and your account from the Properties tab on their Profile, by toggling their Access & Permissions.

Granting Administrator Access will make that Agent an Admin in your helpdesk, who can access the Admin interface and configure your helpdesk's settings.

Granting Administrative access gives the individual all Admin permissions, i.e., there is no area of the Admin Settings that they are unable to configure.

Giving an Agent Administrator Access automatically grants them Reports Administrator Access giving them permission to use and manage all dashboards across the interface.

Reports Administrator Access can be granted without giving an Agent full Administrative Access over the entire helpdesk, this is useful if you want your Agents to be able to use the reporting interface but don't want them to have access to the helpdesk's configuration settings.

By default, the initial Admin that creates the helpdesk will be given Billing Administrator Access. And other Admins can then be granted Billing Access by this Admin.

The initial Admin's Billing Permissions can be revoked once another Admin has been given Billing Administrator Access, but Admins are unable to remove their own Billing Access.

Agent Permissions for Tickets are also limited by Departments: see the section on Department Permissions for details.