To set up custom fields for your 123FormBuilder – Zendesk integration, go to the Settings → 3rd Party Apps section of your form, in
Scroll down to Custom Fields and Tags to associate your form fields with the custom fields created in Zendesk. You’ll find a dropdown list with the text Add custom Zendesk field on the left. Select the custom field from Zendesk you’d want to assign a form field to in the dropdown list and press Add. A line will be immediately displayed below with three columns: Zendesk Custom Field, Form Field and the Zendesk Tag.
You can associate a tag of the custom field associated to the form field if there is one. You’ll need to define the tags in Zendesk in order to associate them to your form fields. If you’ve associated a textbox to a dropdown custom field from Zendesk, only the tag will be send to Zendesk, not the input.
Important: Avoid creating custom fields with the same names as your standard fields in Zendesk, otherwise the integration will not work properly.