What is XML sitemap?
Placing a formatted xml file with sitemap on your webserver, you can enable Search Engine crawlers (like Google) to find out what pages are present and which have recently changed, and to crawl your site fastly and accordingly.
A sitemap is a way of organizing a website, identifying the URLs and the data under each section. Previously, the xml sitemaps were primarily geared for the users of the website. However, Google's XML format was designed for the search engines, allowing them to find the data faster and more efficiently.