Check Out Free Download Email Customizer for WooCommerce v3.17 WordPress Plugin
Email Customizer enables full customization of your WooCommerce emails. Customize colors, header & footer format, add custom links, link to your social networks, and customize what the email says – with [shortcodes] – all using the familiar WordPress Customizer interface. You no longer need to be a developer to do this. And if you still want to you can add your own custom css too.