This article explains how to create an empty linked order through the admin interface. If you’re looking for the programmatic way to link two orders, please read this article.
From the edit order screen
The easiest way to create a linked order is to open the order edit screen and look for the Linked Orders meta box right beneath the Order Notes meta box.
If the order being edited can have children orders, and the user you’re logged in as has the necessary capabilities, the button Add new child order will be present as illustrated below:
Simply clicking on the Add new child order button will create a new empty order with the same billing and shipping address as the parent order, and link the two.
From the orders list table
It’s also possible to create linked orders from the admin list table for orders. First, you need to make sure that the Actions column is enabled in the Screen Options available in the top-right corner of the screen as visible in the following image:
If the Actions column is visible, the order can have child orders, and the user you’re logged in as has the required capabilities, you should see an action that looks like a “+” sign. Clicking on it will create a new empty order with the same billing and shipping address as the parent order, and link the two:
Viewing the links
Creating the links between orders is just step 1. To learn more about how to recognize these links visually, read this article.