You could use woocommerce_order_status_changed
hook for example to notify someone each time an order change of status, like in this example:
add_action('woocommerce_order_status_changed', 'send_custom_email_notifications', 10, 4 );
function send_custom_email_notifications( $order_id, $old_status, $new_status, $order ){
$to_email = 'john.doe@gmail.com'; // <= Replace with your email custom field (the recipient)
$shop_name = __('Shop name'); // Set the shop name
$admin_email = 'shop@email.com'; // Set default admin email
$subject = sprintf( __('Order %s has changed to "%s" status'), $order_id, $new_status ); // The subject
$message = sprintf( __('Order %s has changed to "%s" status'), $order_id, $new_status ); // Message content
$headers = sprintf( __('From: %s <%s>'), $shop_name, $admin_email ) . "\r\n"; // From admin email
wp_mail( $to_email, $subject, $message, $headers ); // Send the email
}
Code goes in functions.php file of your active child theme (or active theme). Tested and works