In ProWorkflow there are three types of Users - Staff and Clients, which also be associated to Organizations.

Staff can be found under the "Staff" heading at the top of the screen:

Clients can be found under the "Clients" heading at the top of the screen. The Clients page primarily refers to Client Organizations, the individual clients you interact with can be found as users within these Client Organisation profiles.

Users of any type can then be assigned a Role. Permissions for Roles can be customized in the Roles & Permissions section of your setting.