Q: how to add wp-user fields to front-end form I've found all kinds of information on how to add user-meta fields to a front-end form. However, I can't find how to add email and the change password.
I found the form fields in user-edit.php, but what to use in place of update_user_meta()? 

A: Something like this should point you in the right direction:
function updateUser($newPassword = '', $newEmail = ''){
    $update = array();
    if(!empty($newPassword))
        $update['user_pass'] = $newPassword;
    if(!empty($newEmail))
        $update['user_email'] = $newEmail;
    if(!empty($update)){
        $update['ID'] = wp_get_current_user_id();
        return wp_update_user($update);
    }
    return;
}

See wp_update_user() for more info on how that function works.  You should also verify the source of the post data with a nonce.
