Meta Data is information that is included with a web page, but humans don’t usually read it. Instead, it is meant to give instructions to a web browser, or a search engine bot.
All of our web pages should have a title. Most browsers will place this title in the title bar of the browser window, and perhaps use part of it on a tab to help you select one of the web pages you have open.
If a meta description is provided, many search engines, including Google, Bing, and Yahoo, may use it to help provide a description of the page.
We can place a list of words that you would like search engines to use to index your web page(s). These were very important a decade or more ago, but because so many people abused them, search engines today either ignore them or pay very little attention to them.
Open Graph Protocol
If your website includes Open Graph Protocol information, then social media sites like Facebook can use that information to give a better description or photo when you post a link to your website. We will usually do at least one set of OG information for the site that will be repeated for each page. We might want to do more if you will often be posting a a link to page other than your home page, and different information would be better. You can find much more information about the Open Graph Protocol here.