how to use target _blank in html code example

Example 1: where to use .target command in html

<a target="_blank" href="">

Example 2: link_to target blank

link_to "External link", "http://www.rubyonrails.org/", target: "_blank", rel: "nofollow"
# => <a href="http://www.rubyonrails.org/" target="_blank" rel="nofollow">External link</a>