I am trying to get documentCaptureURL which is a custom field (78069627) declared in our app, even though the custom field carries the value which shows in the zendesk UI (left hand side panel), but below json doesn't show the value when I try to get using zendesk api as below
zatClient.get('ticketFields:custom_field_78069627')
"ticketFields:custom_field_78069627": {
"hasOptions": false,
"isRequired": false,
"isVisible": true,
"label": "Document Capture URL",
"name": "custom_field_78069627",
"type": "text",
"isEnabled": true,
"requiredOnStatuses": []
}

You should have access to all of the fields available on the form whethere you're hiding them or not. Just to clarify, is this field purposely being hidden from the agent UI? Is it part of the form you're working with? If you do client.get('ticketFields') to list all of fields of the ticket's form you're working on, do you see it there?