Disciplines and Subsectors are configurable lists which when added can help to custom-categorise your Clients, Vacancies and Placements. This can be useful for the person viewing the record and useful for reporting purposes.
After initial configuration during the implementation stage, these will be editable. To edit, a designated system administrator in your organisation will have set permissions in place.
See below to find where they are within Mercury.
Vacancy:
Placement:
The Placement is the only record where these fields are not on the front page. They appear on the Admin & Activities tab:
Client:
NOTE: Discipline is hidden as standard on the Client record but can be unhidden, upon request (as can be seen in the above screenshot).