Meta tags consist of two main elements: meta description, and meta keywords. Meta tags are placed in the HEAD section of the HTML structure of your page. The information contained in those tags is usually not meant for the users but for the search engines. It helps them determine what the page is about. Therefore it might be worth to set them manually for each page or post within your blog.
If you’re using WordPress then all meta tags for each page or post can be set using the All In One SEO Pack plugin.