To configure the XML sitemap in Magento 2 please go to Marketing > Seo & Search > Site Map. Choose an existing sitemap to edit or if you don't have any XML sitemap yet press the Add Sitemap button.
Then you have to set the name of the XML file of the sitemap in the Filename field, enter the Path where it will be located and press the Save & Generate button.
Once you have finished you'll see the list of Sitemaps. Press Generate a link to generate an XML Sitemap file. Note that a sitemap file is updated automatically by cron, you need to press "Generate" only if you want to update/generate Sitemap XML instantly.
A standard Magento 2 XML Sitemap consists of links for products, categories, static pages, and product images.