What is the purpose of a sitemap?

What is a sitemap? A sitemap is the file in which you provide information about the pages, videos and other files on your site and the relationships between them. Search engines like Google read this file to crawl your site smarter. The sitemap notifies Google of pages and files on your site that you consider important, and also provides valuable information about these files: for example, when the page was last updated for pages, how often the page has changed, and the alternate language versions of the page.
Do you need a sitemap?
If your site’s pages are linked correctly, Google can usually discover the vast majority of your site. However, a sitemap can improve the crawl of larger, more complex, or more specialized files. Because Google processes rely on sophisticated algorithms for crawling, it is not guaranteed that all the web pages listed in your sitemap can be crawled or indexed when you use a sitemap. However, in most cases, you will see the benefit of sitemap on your site and it will have no negative effects.
in what situations you may need it?
If your site is really big. As a result, Google web crawlers are likely to skip crawling some new or recently updated pages.
If your site has an archive of many content pages that are isolated from other pages or are not too linked to each other If your site’s pages don’t reference each other naturally, you can list them in a sitemap so Google doesn’t skip some of your pages.
If your site is new and the number of external links to your site is low. Googlebot and other web browsers crawl the web by following links and moving from one page to another. As a result, Google may not discover your pages if no other site links to your pages.
If your site has a lot of rich media content (videos, images) or is featured on Google News. Google may consider other additional information in sitemaps where appropriate.
in which cases you may not need a sitemap?
Your site is kind of “small”. That is, your site has about 500 pages or less. (This total includes only those pages you deem necessary in search results.)
You are on a simple site hosting service (like Blogger or Wix). If your site is on a service that helps you quickly build with preformatted pages and navigation elements, this service can automatically generate a sitemap for you, you don’t have to do anything. Find out if the sitemap is automatically generated by searching for the word “sitemap” in your service’s documentation, or whether it is suggested to be created by you (in this case, how the sitemap is submitted on your hosting service).
Your site is extensively linked internally. This means: Google can find all the important pages on your site by starting from the home page and following the links.
You don’t have many media files (videos, images) or news pages you need to appear in directories. Sitemaps can help Google find and understand video and image files or news articles on your site if you want them to appear in Google Search results. If you don’t need them to appear in Images, Video, or News results, you may not need a sitemap.