Custom event fields are additional event fields that can be added to the 'Event Properties' page and store custom event information. If they are critical to the event set up, they can be made mandatory. Custom event fields can be used for reporting, or for merging the shared content into emails.
Creating a custom event field
Custom Event Fields are set up at account level by a user who has access to the "System Settings" menu (cogs icon):
Go to System settings (cog icon) > Database > Custom Event Fields
Enter a name for your prompt
Decide how you will be capturing the data from the "Prompt Type" drop down
Select "Mandatory" if the setting is critical to your event set up
Your event prompt will appear at the bottom of the list
Select the "Active" check box to enable your custom event field
Your custom event field will now appear in the 'Custom Event Fields' panel on the Setup > Event > Properties page.