1
Log in to your cal.com account
2
Open the event-type from the
cal.com/event-type page and click on -> Advanced tab3
Enable the toggle that reads
Requires Confirmation4
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.

