Meta tags provide metadata about the HTML document (web page). Metadata will not be shown on the page, but will be read by search engines and web browsers.
Meta tags are typically used to specify page description, keywords, author of the document, last modified, and other information about the page. Here’s where it gets confusing: Not all search engines use all of the available meta tags. For example, the keywords meta tag is ignored by Google because so many people thought it was a good idea to stuff that tag full of keywords in the belief that that is how you “do SEO”. Now, the use keyword meta tags may even be considered to be a signal that the page is spam.