Extending Table fields allow you to create a custom table that appears in the Information box on a Contact Profile page.
Steps
Go to the Create/Edit Event Category page
In the Guest Background Information section, set the setting to Yes to display the Guest Background Information table
Search for the Extending Table field by name and select it by ticking it
Press Save Changes at the bottom of the page
Related articles
Design an Extending Table
Populate an Extending Table while creating or editing a Contact record
View an Extending Table on the Contact Profile page
View an Extending Table on an event page in the Guests table