What is XML Sitemap? How is it important?

Xml sitemap is depicted the information about web pages of your websites
Due to xml sitemap, Google can easily crawl your website

XML Sitemaps are important for SEO because they make it easier for Google to find your site's pages.

XML Sitemaps are important for SEO because they make it easier for Google to find your site's pages—this is important because Google ranks web PAGES not just websites. There is no downside of having an XML Sitemap and having one can improve your SEO, so we highly recommend them.

XML sitemap is a coded sitemap used to submit in webmaster tool to help spiders crawl them and index the webpages in search engines.

You can check this article which explains all sitemap file types and when to use:
https://www.microsystools.com/products/sitemap-generator/help/website-sitemap-kinds-comparison/

An XML sitemap lists a website's important pages, making sure Google can find and crawl them all, and helping it understand your website structure:
XML Sitemaps are important for SEO because they make it easier for Google to find your site's pages—this is important because Google ranks web PAGES not just websites.

An XML sitemap is a way for website owners to tell search engines about all the pages that exist on their website.