What is an internal link:
Creating a link on your website to another page on your website is called an internal link, meaning it is all happening inside your website.
Using these types of links has positive effects on SEO. A great example of this is Wikipedia, with tons of links to its own pages.
There are several types of internal links. In addition to links on your homepage, menu, post feed, etc., you can also add links within your content. We call those contextual links. Contextual links point your users to interesting and related content. Moreover, they allow search engines to find out what content on your site is related and determine its value. The more links an important page receives, the more important it will seem to search engines. Therefore, good links are crucial to your SEO.