A sitemap is a file which includes the different pages of a website and the route to them through the sections of the site. The webpages can be arranged visually or as plain text and such a file is very useful for 2 reasons. The first one is that it makes it a lot easier for the website visitors to discover a certain page they need, which means that they can navigate your website better and much faster, that in turn will increase their user experience and it'll be more likely that they will return to the Internet site or will recommend it to other people. Another reason is that a sitemap permits search engines to index your site content better, particularly when it is updated, so when users are searching for certain content, it's more likely that they'll come across your website because it will be listed higher in their search engine results. If your website is not indexed properly, it may not show up for some searches, so even in case you have what people need, they will simply not get to the site.