Google "Woocommerce custom emails" for a plugin. There are a few. But because that email template is generated by the Alidropship Woo plugin, I'm not sure if those custom email plugins would work on it. But no harm in trying. Either they work or they don't.
If they don't. You can click the "Manage" button to the right of the Shipped Order email, then down the bottom you will see a link to copy it to your theme folder. It will create a new folder in your theme folder called Woocommerce and place the copy there. Then you can download it, edit it, then re-upload it. It will over ride the original one.