the bare minimum <meta> tags for sharing on social media:
<meta property="og:title" content="European Travel Destinations">
<meta property="og:type" content="article" />
<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">
// Reconciling the guidelines for the image is simple: follow Facebook’s recommendation of a minimum dimension of 1200×630 pixels and an aspect ratio of 1.91:1, but adhere to Twitter’s file size requirement of less than 1MB.
to test - Facebook Sharing Debugger and Twitter Card Validator.