Add custom text to WooCommerce Email Templates for Wholesale Customers

/**

 * Add custom text to the Completed Order email for wholesale customers only.

 */

add_action( 'woocommerce_email_before_order_table', function( $order, $sent_to_admin, $plain_text, $email ) {

    // Only target the Completed Order email

    if ( 'customer_completed_order' !== $email->id ) {

        return;

    }

    $customer_id = $order->get_customer_id();

    if ( ! $customer_id ) return;

    $wholesale_roles = [ 'wholesale_customer', 'wholesale_vip' ];

    $user = get_userdata( $customer_id );

    if ( ! $user || ! array_intersect( $wholesale_roles, (array) $user->roles ) ) {

        return; 

    }

    if ( $plain_text ) {

        echo "\n\nThank you for your wholesale order! Your dedicated account manager will be in touch shortly.\n\n";

    } else {

        echo '

        <div style="margin-bottom: 20px; padding: 15px; background-color: #f8f8f8; border-left: 4px solid #333;">

            <p style="margin: 0; font-size: 14px; color: #333;">

                <strong>Thank you for your wholesale order!</strong><br>

                Your dedicated account manager will be in touch shortly. 

                If you have any questions, reply to this email or call us on <strong>+1 800 123 456</strong>.

            </p>

        </div>';

    }

}, 10, 4 );