In the Order Synchronization section you can see a select option with 2 options for “Post to Sendle API for the selected shipping method” like the following screenshot. If you choose “For Sendle Only” the order will be posted to sendle for orders where sendle was selected by the customer only. Or if you choose “For All Shipping Method” the order will be posted to sendle for any shipping method chosen by the customer in the frontend.
