Billetto has a guest checkout which helps conversions for ticket sales, all that is required is an email address and name to make a purchase (No account sign ups!)
Ticket buyers can create an account which allows them to manage their purchased tickets, for Billetto to support in case of issues and for better management as an organiser.
Entrants need only state their full name and email, and the ticket will be sent to them when they sign up for your event.
You may, however, as the event organiser, choose to add additional information fields that your ticket buyers will need/can choose to fill out as they make their purchase, such as 'Age' or 'Membership'.
You can add additional fields by clicking on 'Booking questions', which is on the left under the subheading Settings, and can be found by first clicking on 'My events' and then 'Manage' and then 'Customisations & Design'. Be aware that you will need to create your event page first before adding these additional fields.