What a sitemap is for
An XML sitemap lists the pages on a site you want indexed. It does not make pages rank, and it is not a substitute for pages being linked to — it is a hint that helps a crawler find things it might otherwise miss, particularly on large sites, new sites with few inbound links, and pages buried deep in the structure.
What actually matters in a sitemap
Less than most guides suggest. Google has stated publicly that it ignores changefreq and priority. lastmod is used, but only from sites that report it accurately — setting every page's lastmod to today on every deploy teaches Google to distrust the field entirely.
The things that do matter: every URL should be absolute, canonical, return a 200, and be indexable. Listing a URL that redirects, 404s, or carries a noindex tag sends a contradictory signal.
After you generate it
Save the output as sitemap.xml at your domain root, add a Sitemap: line to your robots.txt, and submit it in Search Console. To check the meta tags on the pages you are listing, use the meta tag generator.