Some webmasters use the noindex robots tag for pages that have nearly the same content as other pages on the website. These can be filtered pages, category pages, etc.
Is it an issue for Google if you link to these ‘noindex’ pages from other pages of your website? Google’s John Mueller said on Twitter that this is not a problem:
I don't see a problem with that.— John ☆.o(≧▽≦)o.☆ (@JohnMu) 20. April 2018
How to check the internal structure of your website
The website audit tool in SEOprofiler helps you to check the internal structure of your website. You will get information about the indexability of your web pages, the click-depth that is needed to reach your pages, information about errors on your pages, and a lot more.
You can get an immediate audit by creating a free SEOprofiler account: