What is a web page?
A web page is rather a complex object. What we see on screen is only a part of it. The page has both “visible” and “invisible” components. The searcher is interested only in the "visible" and a few "invisible" text elements. The rest of the web page has nothing to do with the search.


Search engines process only the following "visible" components of the web page code: the title of the web page, words in the web page i (URL), and text in the body of the page.
The main "invisible" components of the web page are contained in the so-called page description and keywords metatags. Other invisible components are of technical nature and do not affect web search. Description and keywords metatags are hidden from sight and do not appear on screen, but they are very important for ranking results by search engines. Also, sometimes you cannot find your keywords anywhere on the page because they are "hidden" in metatags. How can you see "invisible" components? Very simple. Right-click on the page body (not on links or images) and then click on "View Source", or similar item, in the pop-up menu.
Anyway, the metatags are of little interest here because Google gives us no direct control over searching them.
Understanding the structure of the web page and keywords in it is an essential knowledge for using advanced search techniques.