There are a couple different ways you can create an HTML sitemap.  The easiest is to use a plugin if your CMS is WordPress but you could waste time trying to find the perfect plugin.  For example, I created this HTML sitemap for my website using Elementor.  All I did was type sitemap into the search box, put the icon on the page and made a few changes.  It was very simple but it's not the fanciest design.