Meta Tag or Meta Data is the information about any web page. Multiple Meta elements can be used on the same page, but its attributes will be different. Meta Data can be used to specify page description, keywords and any other meta info that's not provided through the other head elements and attributes. The cool term about Meta data is they will not be displayed on the page, but will be machine parsable.
Where to Put?
The <meta> tag always goes inside the head element. The Meta Tag can be used by browsers (how to display content or reload page), search engines (keywords), or other web services.
Example of Meta Data:
<meta name="keywords" content="HTML, CSS, XML" />
<meta name="Author" content="Sohel Parvez" />
Above Two Meta Tag Describing it has 2 parts, 1st one called Properties & 2nd one called Value.
Meta Properties: Meta Properties is the first part of meta tag body & decide what will be Meta Value. Some Meta Properties is Keyword, Description, Author, Content-Type, Zip Code & Many More.
Meta Value: we can call it Description of meta properties. it describe about what is meta value? If you input a meta element like "keyword" you need to input web page keyword on value field.
Why Meta Tag SO Important?
Meta elements provide information about any Web page, most often to help search engines categorize them correctly. They are inserted into the HTML document, but are often not directly visible to a user visiting the site.
They have been the focus of a field of marketing research known as search engine optimization (SEO), where different methods are explored to provide a user's site with a higher ranking on search engines. In the mid to late 1990s, search engines were reliant on meta data to correctly classify a Web page and webmasters quickly learned the commercial significance of having the right meta element, as it frequently led to a high ranking in the search engines — and thus, high traffic to the website.
As search engine traffic achieved greater significance in online marketing plans, consultants were brought in who were well versed in how search engines perceive a website. These consultants used a variety of techniques (legitimate and otherwise) to improve ranking for their clients.