You can hide/show a field depending on certain criteria. To customize the visibility of a field, check the box for Customize visibility under Field options:
The sub-options for customizing the visibility of a field are:
Choose this if you want to hide the field completely from the participant.
Show field for
Choose this if you want to show this field for specific ticket(s). For example, in the case above, the selected field will only show for the VIP ticket.