The title tag (<title>) is used to indicate the title of a webpage to search engines.
The title tag is one of the most important SEO related elements on the page, and may be implemented by Google and other search engines as the main title in a search engine result snippet.
The title tag should be located in the <head> area of a webpage.
Example
Here is an example of a title tag:
<title>Example title tag</title>Why isn’t Google using my title tag?
Google doesn’t always use your title tag as you would like it to be shown in Google search results.
This is normal. Though it can be reflective of your title tags not being correctly optimised.