curl --request POST \
  --url https://services.leadconnectorhq.com/locations/{locationId}/customValues \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'Version: <version>' \
  --data '
{
  "name": "Custom Field Name",
  "value": "Value"
}
'

{
  "customValue": {
    "id": "rWQ709Pb62syqGLceg1x",
    "name": "Custom Field",
    "fieldKey": "{{ custom_values.custom_field }}",
    "value": "Value",
    "locationId": "rWQ709Pb6dasyqGLceg1x"
  }
}