Custom ticket fields are typically used to gather more information about the support issue or product or service. You can add custom fields to your tickets for agents and you can also add them to your Help Center Submit a Request form if you want end-users to see the custom field. Custom ticket fields can be required or optional.
The drop-down list, multi-select, and checkbox custom fields generate tags that can also be used in automations, macros, triggers, reports, and views. All custom fields can be referenced as placeholders (see Using placeholders for custom fields).