Add tracking number to “Completed” email

Hello,
I would like to add include the tracking number in the WooCommerce completed email, this is pretty basic functionality. Several customers write separately to request the tracking number.

I don’t see an option for this in the Order Sync menu.

How can I add the tracking number to the email sent? I know you have a separate tracking plugin, but that is overkill, I don’t want to add another plugin. This data is stored, I just want to add it to the email.

Thanks,
Tom