Thanks guys. When I looked at woocommerce>template>email>admin-new-order.php and customer-completed-order.php the codes look the same.

Here is the customer received email

Here is the admin received email

Sorry, I’m new to wordpress templating and I don’t know which file is responsible for outputting that download link line. Or is it in woocommerce>include>emails>class-wc-email-customer-completed-order.php and class-wc-email-new-order.php files?