Hyperlinks: Before your content can rank, it needs links. Google finds your posts and pages best when they’re linked to from somewhere on the web. Internal links also connect your content and give Google an idea of the structure of your website. They can establish a hierarchy on your site, allowing you to provide the most important pages and posts more link value than other, less valuable pages. So using the right internal linking strategy can boost your SEO! – Yoast.
In the text on a web page, you can put a key word or phrase like “SEO” with a link to another page about “SEO”
Search engines believe that if “SEO” is important enough to have a link to another inside page, then they are more relevant to a visitor’s search.