Hide "Send the new user an email about their account."

hide_notify_register_from_new_user_form.php

add_action( 'user_new_form', 'fn_hide_notify_register_from_new_user_form' );
 
function fn_hide_notify_register_from_new_user_form() { 
    echo '<script>jQuery(document).ready(function($) { 
        $(".user-new-php #send_user_notification").closest("tr").hide(); 
    } ); </script>';
}