If ticket buyers register online, you can, as the organizer, ask them for a number of details. You set this under Settings - Ticketing - Registration.

By default, we ask for name and email address when registering, because tickets are sold by name and sent to an email address. For other data, you choose for each field whether this is not visible (Hidden), can be filled in (Optional) or is mandatory (Required). The less information you ask for, the easier it is for ticket buyers. If information such as gender, location and age are known, you will see this reflected in graphs via Marketing insights.

You can choose to use reCAPTCHA per registration. This is an online check to see if the respondent is an automated script.