A Mandatory Field is something that the user must complete in order to save the event or function booking. This will be indicated by a red star next to the field. You have four choices in this section, however you can make attributes mandatory within the 'Attributes' area of configuration.
To activate a mandatory field: Choose the header on the left for 'Events' or 'Enquiries and select the tick box and save.
If you have activated a field after a booking has been made it will only become mandatory for that event once someone re-opens it.
All new bookings made after any changes will have the mandatory field activated.