Either you work with a hook
function include_customer_details( $order, $sent_to_admin, $plain_text, $email ) {
// Only admin need to know.
if ( !$sent_to_admin ) {
return;
}
// test first, then delete the line below and complete the if statement
echo '<pre>', print_r($email->id, 1), '</pre>';
/*
if ( $email->id == 'paste result from test mail' ) {
echo 'my extra text';
}
*/
}
add_action('woocommerce_email_customer_details', 'include_customer_details', 10, 4 );
Or adjust the template file, because you have access to $order you can get easily order info
More information:
https://businessbloomer.com/woocommerce-easily-get-order-info-total-items-etc-from-order-object/
<?php
/**
* Admin auction finish email
*
*/
if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly
$product_data = wc_get_product( $product_id );
?>
<?php do_action('woocommerce_email_header', $email_heading, $email); ?>
<p><?php printf( __( "The auction for <a href="https://wordpress.stackexchange.com/questions/359270/%s">%s</a> finished. Winning bid is %s. ", 'wc_simple_auctions' ),get_permalink($product_id), $product_data->get_title(), wc_price($product_data->get_curent_bid())); ?></p>
<p><?php echo '<pre>', print_r($product_data, 1), '</pre>'; //etc... ?></p>
<p><?php do_action( 'woocommerce_email_customer_details', $order, $sent_to_admin, $plain_text, $email ); ?></p>
<?php do_action('woocommerce_email_footer', $email); ?>