The default roles an employee will receive are outlined HERE. Any additional roles required in the system will need to be assigned using the Access Request Form by an employee's HR Supervisor. This tutorial outlines how a supervisor can assign additional roles to an employee by copying roles that have been previously assigned to another user.
Note: UGA FMS approval roles are assigned/maintained by a distributed unit's CFO Approver. To add/update/remove approval roles (Expense Manager, Spend Approver, journal Approver), please work with your school/college/unit's CFO Approver.
Tutorial Resources
Security Roles Spreadsheet