Site verification is the process of proving that you own the site or app that you claim to own. Google needs to confirm this ownership because once verified, the owner will gain access to the site’s private Google Search data. In addition, the site's owner will also be able to affect how Google Search crawls the website.
Site verification is one of the steps to take when using Google Search Console, a free service offered by Google that helps users monitor and maintain their site's presence in Google Search results. It’s not required to sign up for Search Console for a site to be included in Google's search results. However, doing so can help the site’s owner understand how Google views the site and optimize its performance in search results.