You can easily insert title and nofollow information into each link manually via the WordPress Text editor. It goes something like this:
<a title="ADDITIONAL LINK INFORMATION" href="URL" rel="nofollow">
EDIT LINK TEXT</a>
If you like using the WYSIWYG editor and all the tools that come with it, then you’ll love how this plugin modifies the link settings modal.
Here is part of the write up from WPBeginner:
Often SEO experts recommend that you use rel=”nofollow” attribute on external links. This attribute tells search engines that they can crawl these links, but you don’t want to pass away any link authority to these websites…
Adding Title and NoFollow Fields in Insert Link Popup
First thing you need to do is install and activate the Title and Nofollow For Links plugin. It works out of the box, and there are no settings for you to configure.
Simply edit or create a new WordPress post and then click on the insert link button in the post editor. The insert link popup will appear, and you will notice the restored Title field and a checkbox to add the nofollow attribute to the link.
I wondered at what the Title attribute actually does, and I got mixed results from my research. Some say it assists with SEO. Others say the majors search players don’t give the text in the title attribute much weight, and it doesn’t matter.
Some say it assists with accessibility, but others say screen readers don’t use it. An article titled “I thought title text improved accessibility. I was wrong.” actually makes that case fairly convincingly.
For me, I will not be using the Title attribute.
Links be default are “follow” links, which means search engines count your link to a particular website as a boost for that website in the search rankings. NoFollow means the link to a particular website will not be counted by search engines. This WordStream article defines these types of links very well, if you are interested in more reading.
The article quoted above mentions giving away “link authority” and it is further explained by the author in his comments that you would want to protect your site’s search rankings by adding NoFollow when linking to sites that you may not trust so much. Basically, if you boost too many sites that are “junk” your site’s rankings start hurting.
I will likely use NoFollow, but only sparingly.