Many websites have pages that show sitemaps — a hierarchal list of pages within a site. For our purposes, a sitemap is an XML file that resides on your server and is read by Google and other search engines to learn about your site.
If you've ever worked with Google Webmaster Tools (https://www.google.com/webmasters/), you're familiar with the concept of providing a sitemap URL to Google. By doing so, Google can become fully aware of the pages and products within your Magento store without having to figure it out themselves. Sitemaps are an important component of your Search Engine Optimization (SEO) efforts.
Magento 2 has a built-in sitemap functionality that you can configure to generate sitemaps for each store view within your installation.