To set requires confirmation configuration, you simply need to:

1

Log in to your cal.com account
2

Open the event-type from the cal.com/event-type page and click on -> Advanced tab
3

Enable the toggle that reads Requires Confirmation
4

From here, -> Select Always if you want it to be an event-type that requires confirmation at all times -> Select When booked with less than {{ num }} {{ time }} notice to only make it an opt-in event type when a booking is made within the selected/configured time-frame.