A sitemap, or site map, is a file used to provide information about pages, videos, and other files on a website and indicate the relationship between them. Search engines like Google will read these files to crawl your site more intelligently. Sitemap is a term used on the internet and intranet and has two meanings:

A sitemap is a list of pages on a website. There are two types of sitemaps:

• HTML : This type of sitemap, usually organized by topic, helps users navigate a website.
• XML : This type of sitemap provides crawlers with a list of web on a website.

A list of URLs on your website that crawlers can use to discover and index your content.

The sitemap for SEO

The sitemap tells Google which pages and files you consider most important on your site and provides valuable information about those files: for example, when the pages were last updated, how often they were changed, and versions in alternative languages.

Sitemaps in Search Console

Daniel Waisberg provides a brief overview of the sitemap report in Search Console. Learn more about what a sitemap is, decide whether you need one or not, and learn how to submit a sitemap and track its status using Search Console.

XML Sitemap

An XML Sitemap search engines need to know about.

XML sitemaps provide search engines with an efficient list of URLs on a website. They are simply text files marked with tags that identify data . The URL for an XML sitemap is typically located at the root of the site's structure.

Image sitemap

A sitemap contained only the URLs of the images on a website. Add images to an existing sitemap or create a separate sitemap just for your images. Adding images to the sitemap helps Google detect content that might not be found (for example, images that your website uses JavaScript code to localize).

Video sitemaps and video sitemap alternatives

A video sitemap is a site map that contains additional information about the videos hosted on your webpage. Creating a video sitemap is a great way to help Google find and understand the video content on your site, especially content that has been recently added or that we can't discover through general crawling mechanisms.

The Google Video sitemap is an extension of the standard sitemap.

Google News Sitemaps

A Google News sitemap is a file that allows you to control the content submitted to Google News .

Websites with a Google News sitemap are not favored in ranking results. Google News uses standard crawling methods to search and label the home pages and sections of all news websites, regardless of whether a corresponding sitemap is available.

How to manage sitemaps with the Sitemaps Report

Use the sitemap report to manage sitemaps. Use the sitemap report to generate information about your property's new sitemap, view its submission history, and identify errors that Google encountered during preview.

Do I need a site map?

Generally, if the page links are correct, Google can detect most of the site's content. Even so, sitemaps can still improve the crawling of larger or more complex websites or more specialized archives.

Reference: https://developers.google.com/search/docs/advanced/sitemaps/