What exactly gives sitemap

[Jastrzab]

Maybe it's a little stupid question, but I  submited sitemap.xml in google webmasters tools and I didn't observe any difference when sitemap.xml exist or not. Googlebots follow after links in Internet. Sitemap (in form xml) in some way help them to index? 

[XML-Sitemaps Support]

Hello,

here are more details about sitemaps: https://www.xml-sitemaps.com/about-sitemaps.html

[Sika]

Should I place on my website link to the file sitemap.xml or only submit in search engines webmasters tools.

[XML-Sitemaps Support]

Hello,

there is no need to link to xml sitemap from your pages, just submit it to search engines.

[Prez]

Should I place on my website link to the file sitemap.xml or only submit in search engines webmasters tools.

If you put link to sitmap.xml on your website, then your sitemap  will be involve in google index, but probably in supplemental index.