What columns should my sitemap CSV have?

At minimum, your sitemap CSV needs one column: URL. The standard sitemap protocol defines three optional fields that become columns when present: Last Modified (lastmod), Change Frequency (changefreq) and Priority (priority). If you converted from a sitemap-index, add a Source Sitemap column so you can trace each URL back to the child sitemap it came from. xmlsitemapmaker.com adds these conditionally — if the sitemap doesn't declare priority or changefreq, those columns are omitted rather than filled with empty strings. Wider columns (image URLs, video metadata, alternates for hreflang) are excluded by default because they bloat the file and most workflows don't need them.