Apart from these hooks, the WooCommerce hooks section also includes an option known as a custom hook. This action hook allows you to add dynamic content to your email template. Using this custom hook, you can provide order meta fields, include checkout field values, add the current email status like on hold, processing, and much more. Also, it allows the users to display the shortcode from third-party plugins.
To use the Custom Hook:
Open the builder > Choose a layout > WooCommerce Hooks > Custom Hook.
Once clicked on the custom hook, the {custom_hook_name} gets added to the template builder.
Click on the corresponding edit button of the custom hook to provide a unique name.
It is recommended to change the default name of the custom hook to an informative one to have an idea of what the hook is used for.
So, using the hook name you can write a function and insert the required fields.