Defines the title of the document. The title element is required in all HTML/XHTML documents.
The element:
Page title contents are displayed in search results. A title tag tells both users and search engines what the topic of a particular page is. Ideally, you should create a unique title for each page on your site. If your document appears in a search results page, the contents of the title tag will usually appear in the first line of the results.
Words in the title are bolded if they appear in the user's search query. This can help users recognize if the page is likely to be relevant to their search.
If the user clicks the result and visits the page, the page's title will also appear at the top of the browser by the way. The title tag is not visible on the page itself.