Two dropdowns control the optional hints. changefreq (always, hourly, daily, weekly, monthly, yearly, never) suggests how often a page changes, and priority (from 1.0 down to 0.3) suggests its relative importance. An important detail about this tool: whatever you pick is applied uniformly to every URL in the list — it writes the same <changefreq> and <priority> on each <url> block rather than letting you set them per page. Both are advisory anyway; modern crawlers largely treat them as weak signals and may ignore them entirely, so uniform values are perfectly acceptable.
There is no lastmod field in this generator. lastmod is the field search engines actually pay attention to, since it helps them prioritize re-crawling, so if you need accurate per-page last-modified dates you will add them by hand or use a sitemap your CMS produces. For discovery — simply telling crawlers which URLs exist — the file this tool builds is complete and valid without lastmod.