An XML sitemap is a file used by search engines to understand and index the structure and content of a website. The sitemap is a list of all URLs on the website and contains additional information such as the last updated version of the page, how often it is changed and how important it is compared to other pages on the website.

The use of XML sitemaps can help search engines to search and index the website faster and more effectively. By providing a complete list of all URLs on the website, search engines can also find pages that may not be accessible through internal links or navigation menus.

XML sitemaps can be created manually by creating a list of all URLs on the website together with additional information in an XML format. However, there are also many tools and plugins that can automatically create an XML sitemap for a website.

In summary, an XML sitemap is an important file for the search engine optimisation of a website, as it helps search engines to understand and index the structure and content of the website.