Custom fields are available in Shipstation. I would like to map the channel order number to the shipstation custom field #1 as an example. This way our shipping support team can see the original channel order number, which is what our customers have. Our customers don't ever see the Linnworks order ID, yet our shipping team needs to also communicate with customers and therefore it's easier for our shipping team to refer to the customer's original order (in this case, it's from 3dCart but it can also be from Magento).