Some of the pages of your site serve a purpose, but that purpose isn’t ranking in search engines or even getting traffic to your site. These pages need to be there, as glue for other pages or simply because regulations require them to be accessible on your website. If you regularly read our blog, you’ll know how noindex or nofollow can help you deal with these pages. However, if you are new to these terms, please read on and let me explain what they are, and what pages they might apply to!
What is noindex or nofollow?
Both are settings you can add to your robots meta tag. Want to know more about that? We wrote quite an extensive ultimate guide on the robots meta tag that you should read.
Source : Yoast