Knowledge Graph is Google's way to enhance its search engine's results with information gathered from variety of sources. It appears as an infobox next to search results.
Started in 2012, the Knowledge Graph was once dedicated to those who have a good presence on Google. Individuals and organizations with Knowledge Panels can use Google's verification process to claim their panels and provide authoritative feedback on the information and images presented.
In June 22, 2018, Google is updating that process, as well as extending the verification eligibility to more entities.
Being "verified" here allows owners to control certain elements and data Google has on its Knowledge Panel about them. For example, the panel owners can suggest a feature image or some changes to the data.
The things that cannot be changed, include: subtitle, Wikipedia snippet, images other than the main image, and the "People also search for" section.
According to Google:
In order to get verified, users must search for the entity whey show up for in the Knowledge Panel, to then click on the link at the bottom or below the panel that says Do you manage the online presence for [name]?.
Then they need to login into either YouTube, Google+, Search Console or Twitter, in order "to verify that you’re an authorized representative of an entity on Google."
If users use any other account rather than Google's, Google will automatically stores the association between their accounts.
Once verified, "you can suggest factual changes to information in your Knowledge Panel and suggest a featured image," said Google.