Yes, a sitemap is a way to tell search engines about the pages on your site that they may not otherwise discover. It is an important part of SEO because it helps search engines understand the structure of your website and find all of the pages on it.
A sitemap can be in the form of a simple text file listing all of the URLs on your website, or it can be an XML file that follows a specific format. XML sitemaps are commonly used because they can provide additional information about each page on your website, such as when it was last updated and how often it changes. This can help search engines more intelligently crawl your site and improve the chances of your pages being indexed.
There are many tools available that can help you create and submit a sitemap to search engines. Some popular options include Google Search Console, XML-Sitemaps, and Screaming Frog.