An XML sitemap is a file that contains a list of all the pages on a website, along with information about when they were last updated, how frequently they are updated, and the relative importance of each page. The primary purpose of an XML sitemap is to help search engines discover and index all the pages on a website.

While having an XML sitemap does not directly improve the SEO ranking of a website, it can have a positive impact on SEO in several ways:

1. Improved Indexing: An XML sitemap helps search engines discover and index all the pages on a website. This can ensure that all the relevant pages are included in search engine results, which can help to improve the visibility and ranking of a website.
2. Priority Pages: By providing information about the relative importance of each page, an XML sitemap can help search engines prioritize the pages that are most important to a website’s SEO strategy. This can help to ensure that these pages are crawled and indexed more frequently than other pages on the site.
3. Crawl Optimization: An XML sitemap can help search engine bots crawl a website more efficiently, by providing information about the structure and hierarchy of the site. This can help to ensure that all the pages on the site are crawled and indexed, while minimizing the amount of unnecessary crawling.

In summary, while an XML sitemap does not directly improve the SEO ranking of a website, it can help to improve the discoverability, indexing, and crawlability of a website. By providing search engines with a comprehensive list of all the pages on a website, an XML sitemap can help to ensure that all the relevant pages are included in search results and that the website is crawled and indexed efficiently.