What is a sitemap?
A sitemap is a file where you provide information about the pages, videos, and other files on your site, and the relationships between them. Search engines like Google read this file to more intelligently crawl your site. A sitemap tells Google which pages and files you think are important in your site, and also provides valuable information about these files: for example, for pages, when the page was last updated, how often the page is changed, and any alternate language versions of a page.
Your sitemap file is updated each night. You may manually recreate it in the Site Map Utility.
Submit a Sitemap
You can submit a sitemap to Google Search Console to tell Google about any new sitemaps for your website, to see your sitemap submissions history, and to see any errors that Google encountered when parsing your submitted sitemaps.