What's the role of meta tags in SEO?

Meta tags:

Meta tags are used for a short description of your websites pages The meta tags are gives a short details of your web-page that can be easily understood or read by the search engine or user. The meta tags are can be used as two types- "meta HTTP-equiv" and the meta tags with the "NAME" attribute. In SEO (search engine optimization) the main role of meta tags are make unique keywords differ from others and edit it your own web site.
<meta name="description" content="Type your websites content which are unique from your website's title.">
     The meta tags are contains the some information about the your web page contents and they also used in the head section of your HTML document.
<meta name="keywords" content="Write the unique keywords related to your description and title.">  

Note: The both meta description and keywords must be edited under the head section of the HTML.