Signup bloggers 'Dashboard' select the blog then select the option as shown below
By selecting this option you can see the dropdown Menu
In this Menu select Templete option. Afterclicking Templete option, a new pop up window will open as show below
In this window select Edit HTML option. By selecting this option, a new pop up window will open. In this window select proceed option.
By selecting proceed option. HTML edting window will open. In this window you have to add following Meta Tag Code
DISCRIPTION = Write blog description in detail in few words.
KEYWORDS = Write keywords of your blog.
AUTHOR NAME = Write author name.
In this window find <head> tag and add the following meta tag code next to <head> tag as show below
Now save the template
Meta Tag Code is now added to your blog. Now search engines indexed your blog.