This code snippet will change the native WordPress login URL to your desired URL.

add_filter('site_url',  'my_login_url', 10, 3);
function my_login_url( $url, $path, $orig_scheme ) {
    $old  = array( "/(wp-login\.php)/" );
    $new  = array( "login.php" ); //your new login url
    return preg_replace( $old, $new, $url, 1);
}