MetaTags or Meta tags or known as Meta Data is HTML Element used to create a metadata structure for web pages, this data used by search engine to understand more about web pages and usually contain about small information like description, keywords, author, language, robots option, title, and etc about web pages. Meta Tags hold important role on On Page SEO (search engine optimization), in proper use MetaTags can improve web pages SEO ranking about 10% to 15% (According to some calculation) and all MetaTags data placed between Head section on HTML. This is MetaTags usually used by Webmasters:
Title Tag is your web pages Title which tells about your web pages topic or subject, to creating title tag you need to write it with no more than 70 characters and contain identity about your web pages and content.
Description Tag is small information about your web pages which not exceed 170 characters, better Description tag is not to write your keywords inside but you can include it with keywords phrase but don't write it over and over again that will keywords stuffing and lead you to get penalized cause by over optimization.
Keywords Tag which place to put your web pages keywords, write it not too much like 10 keywords and separate each of them with a comma or "," the keywords must relevant with web pages content.
Robots Tag used to adjust access to your web pages for crawler owned by a search engine.
This Meta used to tell a search engine what language used by web pages, this MetaTag makes search engine easier to sort visitors come from a specific country and served web pages with their language in search engine result.