Featured Snippets in Search Results

At the point when a client poses a question in Google Search, we may demonstrate a query item in an exceptional highlighted snippet obstruct at the highest point of the list items page. This highlighted snippet square incorporates a rundown of the appropriate response, removed from a website page, in addition to a connection to the page, the page title and URL. An included snippet may look something like this on the page:

There are some questions which comes in mind;

According to Google Support Or Search Console Help -

Where does the answer summary come from?

The summary is a snippet extracted programmatically from what a visitor sees on your web page. What's different with a featured snippet is that it is enhanced to draw user attention on the results page. When we recognize that a query asks a question, we programmatically detect pages that answer the user's question, and display a top result as a featured snippet in the search results.

Like all search results, featured snippets reflect the views or opinion of the site from which we extract the snippet, not that of Google. We are always working to improve our ability to detect the most useful snippet, so the results you see may change over time. You can provide feedback on any Featured Snippet by clicking the "Give Feedback" link at the bottom of the box.

Opting out of featured snippets

You can opt out of featured snippets by preventing snippets on your page using the tag on your page. This will remove all snippets on your page, including those in regular search results.

How can I mark my page as a featured snippet?

You can't. Google programmatically determines that a page contains a likely answer to the user's question, and displays the result as a featured snippet.

Is this part of Knowledge Graph?

No, this is a normal search result, emphasized with special layout.
This is very useful for any business who provide a Number to support some products Or services, who have any answer for related question which was asked in search box (query) etc.

Update Source: Google Search Console Help