| Field | Type | Required | Description |
| order_reference[0] order_reference[1] order_reference[2] . . . order_reference[n] | string (40 characters) | Yes | This is order reference number. |
| label_type | string (5 characters) | No | Possible values are pdf and zpl Default value is pdf |
| label_size | string | No | Default value is 100×150 (Width x Height) |
| label_string | boolean | No | Default value is 0 |