The importance of a site map
What is the site map?
The sitemap, also known as sitemap, is an organized list of pages on a website.
This site map serves as an index that informs both the users and the search engines of the organization and the relationship between the pages in a simple and fast way.
When we enter a site looking for something we do not find, an easy way to do this is to go to the site map where, as a general rule, the pages of the site are listed in an organized way.
The site map, in addition to the page address, may contain other information such as the refresh rate or page priority compared to others. Although it does not change the position of the site in search engines, this optional information is used to know which pages the site owner considers most important or the last time the page was updated.

Search engines, such as Google or Yahoo, are already able to traverse the whole site and index, usually in a correct way, the content without the site map. However it is always advised to have one to help and improve this indexing.
For example, recent sites often do not have many links, and search engines use those links to find pages. If you have a sitemap, it ensures that all pages are viewed by search engines.
On the other hand, in sites with a lot of content, some pages may not be considered, which impairs the indexing of the site and consequently the position in the search engines.
In general, search engines can index content properly, but a site map never harms, just helps.