In the form builder, the meeting card has two settings related to hidden fields
Fields Hidden From Requestors
Field Hidden From Everyone
Fields hidden from requestors are fields that will not be shown to users who are using the form to request an event:
The most common use case is to hide setup/teardown times to requests. The fields will then show up in the request dashboard for approvers, and in the event details view for viewing approved events that are in the schedule.
Fields hidden from everyone will be hidden in all views.