Marcin Kijak

After installation you can find “Noindex by path” option in the main menu. This allows you to simply add relative paths 
you need to exclude from SERPs. Add a path (including slashes from begging and the end of the string) and save the 
changes. Since this plugin is called to be “simple” you can add only one path at once, but the process is smooth 
and easy.
Plugin will add “noindex” meta tag which is an instruction for search engines that this particular page should not be indexed. 
Technically it modifies wp_head tag.

Noindex by Path

Ask search engines not to index individual pages by a relative path - which means you can set every url no matter it is a page, category listing or an …

Patryk

The plugin adds a “noindex” field in the edit window for pages, posts and custom post types (CPT), which, when selected – after saving, adds the “noindex” tag to a given page. The tag blocks the indexing of a given page in search engines, e.g. Google.

PRyC WP: Add noindex tag

The plugin adds a "noindex" field in the edit window for pages, posts and custom post types (CPT), which, when selected - after saving, adds …

Noindex by Path vs PRyC WP: Add noindex tag