meta tags are very important for on page seo.without meta tags you cannot achieve high ranking in google or any search engines because meta tags tell search engines about your site description and topics so that they when any one search for your information,you websie may be displayed for that particular information.so meta tags is useful for both search engines and users.
here is the tutorial on how to add meta tags to blogger post.meta tags are generally insert after head seaction of your blog.situation may be different as your template.so you may add meta tags in blogger according to your template.here is the here is the example on how meta tags are place in blogger blog.
<meta content='desc here' name='description'/>
<meta content='keyword here' name='keywords'/>
and so on.you can also add other tags like robots,language and author tags.be careful when adding meta tags because it cannot be changed or if you try to change it you may have some problem.
Tags: blogspot tutorial