You can add as many custom order statuses as you wish, depending on your business rules and processes.
You can get to this page by navigating to Admin Home -> Store Information -> Orders Status
Once there, click the Insert button, type in the new status you wish to add, and click Insert to finalize.
You can also Edit and Delete order statuses on this page.
Note:
If using the OBN One Click to Ship or Order Automation features, we suggest that you not modify any order statuses related to those features, as the system uses certian statuses to maintain order updates. However you can add as many order statuses as you like to personalize your store to your unique business. For example, some retailers have added the statuses "Pending Store Pickup" "Picked Up" or "Customer Follow Up Rqd" etc.
Pro-Tip:
On your orders page, you can sort your orders by Order Status. This allows you to view only the orders that are in a stage that you need to take a certian action on.