The partial shipments option is for sending only part of the order and not every item the customer ordered. For instance, if a customer orders shampoo and soap, but you are out of soap, this option allows you to send just the shampoo and mark the order as Partially Shipped instead of Shipped. Allowing you to go back to the order later and ship the rest of the order.
Click the Settings tab.
Under “eCommerce” select “eCommerce Integrations”.
If you already have a Webhooks integration, select it, if not, select “Add Commerce Integration”.
Select Webhooks
There is a checkbox you can select/deselect to support partial shipments.
Select “Save Changes”.