When you book an appointment for a new guest in the Appointment Book, the
First Name and Last Name fields in the Guest Details section are always mandatory by default. See the following image for reference.
Make Other Guest Details Mandatory
At the organization level, click the Admin icon.
Select Organization > Organizations.
Click the Settings tab.
Expand the Guests section.
Select Show alert if required fields are missing when creating guest profile.
Select the fields that you want to make mandatory.
The next time someone books an appointment for new guest without specifying the selected mandatory details, the Appointment Book displays an alert.
You can even choose to display an alert if someone tries to take payments without specifying the mandatory guest details. To do so, select Block payment if required fields are missing.