A special field refers to a field that shows up prominently throughout the system and cannot be amended to collect different data than specified. Bookwhen currently has three types of special fields:
Attendee name
Attendee email
Child attendee (Is this attendee a child?)
This article covers:
An entry with Special fields
An entry setup with special fields will look something like the below:

Special fields on a booking
Firstly, you will see their name and email addresses under Attendee details. Secondly, you will see their names and email addresses under the event they have booked:

Using special fields makes it a lot easier to track your bookers as the system will have logged them as attendees instead of booking fields.
For example, they will automatically show up in your attendance registers:

And within any reporting, such as a Bookings search:

An entry without Special fields
An entry setup without special fields will look something like the below:

A booking without special fields
Firstly, it will state Name not given under Attendee details, but you will see the booking form fields with their name and email address. Secondly, you will see '1 person' under the event they have booked (as opposed to their name and email addresses):

It's a little more challenging to track your attendees, as they won't automatically appear in your register:

To view the booker name details, you'll need to select the pencil and paper 📝 icon in the top right-hand corner:

From here, select the fields you'd like to see on the register (in this case, 'Name' and 'Email'), then select Save changes:

You will then see the fields on the register, but they are un-clickable:

The names also won't appear from within your direct reporting, such as a Bookings search:

To note: they will appear in your exported CSV file searches alongside your other booking form field questions.
Summary
It's much simpler to have your entries set up with Special fields, as it allows you to navigate the system much more simply and effectively.
If you have any questions regarding this, please don't hesitate to reach out to the support team via live chat or email at support@bookwhen.com.