The Sitemap file helps search engines index your site and find the most important pages easily. If you do not want the Sitemap to appear in Google search results, add the following lines to the .htaccess file in the root directory where WordPress is installed:
<IfModule mod_rewrite.c>
<Files sitemap.xml>
Header set X-Robots-Tag "noindex"
</Files>
</IfModule>Replace sitemap.xml with your Sitemap file name. For more on what a Sitemap is, see the post How to create a Sitemap in WordPress and how to submit it via Google Search Console.