Change register form action url

I have 2 registration forms, default one on /wp-login.php?action=register for “recruiter” users, other one on /wp-login.php?action=register&type=candidat for “candidates” users

My problem is that on candidate form, the form tag still has /wp-login.php?action=register as the action URL, and I want it to be /wp-login.php?action=register&type=candidat

I tried updating wp-login.php file but if I update WordPress in the future, my code will be overwritten

I’ve tried other topics recommanding to use ‘register_url’ hook but it doesn’t seem to work

You could do something like this:

<?php

add_action( 'register_form', function() {
    $get_type = filter_input( INPUT_GET, 'type', FILTER_SANITIZE_STRING );

    if ( ! $get_type ) {
        return;
    }
?>
<input type="hidden" name="type" value="<?php echo esc_attr( $get_type ); ?>" />
<?php
});

This will add the type parameter as a hidden field on the form if it is set in the GET query string.