"The head of an HTML file contains all of the non-visual elements that help make the page work." Can anyone give an example.

Answer 1

take a look at the source code of any website.
or take the html course here.
or visit w3schools.

Answer 2

for example <title> Tag and All Meta Data 1- Description 2-author 3-keywords ,, charset:utf-8 ,, <Link> Tag ,, <style> Tag and <script> Tag