essential-meta-tags-social-media.html

<!--  Essential META Tags -->

<meta property="og:title" content="European Travel Destinations">
<meta property="og:description" content="Offering tour packages for individuals or groups.">
<meta property="og:image" content="http://euro-travel-example.com/thumbnail.jpg">
<meta property="og:url" content="http://euro-travel-example.com/index.htm">
<meta name="twitter:card" content="summary_large_image">


<!--  Non-Essential, But Recommended -->

<meta name="og:site_name" content="European Travel, Inc.">
<meta name="twitter:image:alt" content="Alt text for image">


<!--  Non-Essential, But Required for Analytics -->

<meta property="fb:app_id" content="your_app_id" />
<meta name="twitter:site" content="@website-username">

Source: https://css-tricks.com/essential-meta-tags-social-media