The HTML tag indicates the beginning and the end of an HTML document. All other tags must be placed between <html> and </html>, or they will be ignored by the browser.
head
Information that refer to the document content is written between <head> and </head>.
title
The string written between <title> and </title> appears on the window bar of the browser.
Titles are very important if pages are homepages in WWW, because search robots make there databases by using titles.
body
The body of the document is written between <body> and </body>.