This plugin adds a small JS file in the WooCommerce new order page. This JS makes it possible to automatically perform the shipping calculation based on WooCommerce shipping settinng.
While creating a new order from the Wordpress backend, add a shipping fee as usual. Once you select a shipping method, the calculation will use the order subtotal and customer's shipping address data to perform the same calculation that would be performed if the order was placed from the websites frontend.
It will them match the returned results with the selected shipping method and addthe shipping amount to the relvand input field automatically.