What is Sitemap?
Also known as: XML sitemap
A sitemap is an XML file listing the pages on a site that you want search engines to discover and crawl.
It does not make pages rank; it makes them findable, which matters most for newer sites and for product pages buried several clicks deep in a catalogue.
A good ecommerce sitemap updates automatically as products and categories are added or removed, and is submitted once to Google Search Console.