A sitemap is like a roadmap for your website, helping search engines find, crawl, and index all your pages. It tells search engines which pages are important and provides info about each page. There are two main types: HTML sitemaps for users, making your site easier to navigate, and XML sitemaps for search engines, ensuring they index your important pages.
HTML sitemaps
HTML sitemaps are mainly meant for users. They provide a clickable and ordered structure for your website, making it easier for visitors to travel. HTML sitemaps provide a clear, hierarchical arrangement of your website's pages, allowing search engines better to grasp the structure and importance of your material.

XML Sitemaps
XML Sitemaps are generated for search engines. They include meta tags about each URL, such as when the page was last updated, how frequently it changes, and how it compares to other URLs on the site. XML sitemaps are essential for SEO since they make sure search engines like Google and Bing can find and index all of your relevant pages, even if your internal linking structure isn't flawless.