If you have a page in your site that should not appear in the navigation or sitemap, then you can hide it. To hide the Page in both places open the Navigation tab and expand the Visibility panel. Here, check the checkbox Hide in Navigation and Sitemap.

Check Only hide in Sitemap when you want to hide the Page only from the sitemap. Check Exclude from Search and XML Sitemap when you want to hide the page from search and the XML sitemap.