The availability of URLs on websites for crawling are informed to Google and other search engines through the webmasters of sites and are encompassed under sitemap protocols. Sitemaps can be defined as XML files that list the site URLs. They permit webmasters to include supplementary information about the URLs including the latest updates, modifications, and their order of importance. This information is helpful for the search engine bots to crawl the sites.
Sitemaps are useful when the websites are large in size or have fewer external links or some sections are not browseable.