The Advanced Forms add-on allows you to add any type of fields to your booking forms. You can get any information from your customers, or from each participant of the activity. Then, the data will be bound to the reservation, and for WooCommerce users, they will also be bound to the order item.
You will then be able to see and edit these metadata in the booking list, and filter your bookings according to the custom fields values. These same values can also be displayed in your notifications.
Refer to this documentation to learn how to set up your custom fields and exploit your data. If you still have a question after consulting this documentation, you can contact us at firstname.lastname@example.org.