simple function for adding extra stuff to your Wordpress site's robots.txt

wp-robotstxt.php

<?php

/**
 * author: Robert Danklefsen
 * website: https://www.catchylabs.com/
 *
 * simple function for adding extra stuff to your Wordpress site's robots.txt
 * add to functions.php
 */
 
function catchylabs_addToRoboText($robotext) {
    $additions = "
# Additions
Disallow: /folder/
";
    return $robotext . $additions;
}
add_filter('robots_txt', 'catchylabs_addToRoboText');