WordPress / WooCommerce: notify user admin when user registers and send user meta values if needed

wordpress-woocommerce-send-user-meta-to-admin.php

// Set content type to html if needed
function wp_set_content_type(){
    return "text/html";
}
add_filter( 'wp_mail_content_type','wp_set_content_type' );


function admin_registration_email_alert( $user_id ) {
    // Send to website admin
    $to = get_option('admin_email');
    // Get new user ID
    $user    = get_userdata( $user_id );
    // Get new user email
    $email   = $user->user_email;
    // Get custom user meta field (in my case it is a file url that was uploaded during registration)
    $document = $user->attachment_url;
    // Create message, I enabled wp_mail_content_type html, so i can put file url in href
    $message = $email . ' has registered to your website. <a href=' .$document. '>Business certificate/diploma download</a>';
    wp_mail( $to, 'New User registration', $message, $attachments );
}
add_action('woocommerce_created_customer', 'admin_registration_email_alert');

This small snippet will send user registered notification to website admin along with custom user meta that was created during registration. In my case it is the url to the file that was uploaded during registration.

$document = $user->attachment_url; can be replaced with required user meta.