When publishing sponsored content, SEO experts advise to apply the nofollow attribute to your external links to avoid getting penalized by the search engines. Learn more about why and when you should use nofollow links – Infographic: What Is The Nofollow Tag; When & How To Use It
It’s easy to apply the nofollow attribute to your external links in WordPress. Simply switch the post editor to Text mode, and then add rel="nofollow" in the opening <a> tag.
The rel="nofollow" attribute can appear after the href attribute, and alongside other attributes as well. For example:
<a class="button" href="http://clickwp.com" rel="nofollow" title="WordPress Support">ClickWP</a>
If you prefer to have the rel="nofollow" attribute added automatically, see this post by WPExplorer – How To Automatically Nofollow External Links In WordPress
