The Custom Fields feature gives you the option to add more fields to your booking form so as to customize it to best match your business needs. The customer’s first and last name, email address, and phone number are there by default, but with the Custom Fields feature you can add extra fields if you want to ask a customer a question, collect additional personal details, or for any other reason.
For appointments, these fields will appear on the Booking form under the default fields, and once your customer fills them this information will be shown in the appointment information on the back-end.
As for the events, custom fields will be shown in the same place on the front-end booking form like for the appointments, but when it is about the back-end the place for the custom fields is different and you will find them when you open the Attendees list and click on any attendee. Once you click on the attendee on the list you will see an option “Edit attendee” and by clicking on that option the custom fields will show up.