More information about the protocol (OG) on the official website: ogp.me
An example of Open Graph markup for the page you are currently viewing.
The Open Graph protocol was created to mark up information on the pages of the site so that the user, when clicking on the share buttons, could get a publication whose appearance is set by the site developer and (in theory) looks more attractive than with the same user action, but without (OG) markup.
Open Graph markup allows your website page to become a source of information in social networks. In particular, you can set objects that are important on the page, such as title, type, image, and a direct link to a web page. These are mandatory meta tags that are set for the selected object, but there are a number of other options that relate to specific types of information, such as videos.
Main OG markup meta tags:
og:title - the name of your object,
og:type is the type of your object,
og:image is the URL of the image,
og:url is the direct (canonical) address of your object.
See also: What is the optimization of posts for VKontakte and Telegram?