Internal linking refers to a link on a page that points to another page on the same website. Internal linking is important because it helps strengthen those keywords internally for those pages, it allows users (and search engine robots) to navigate through the website, and it tells the search engines that the page is relevant for that keyword phrase.
A website is a collection of many types of content. Your website can contain a collection of content including blog posts, product descriptions, images that highlight your product, explainer videos that tell your story, and contact information. These different types of content have one thing in common. Each piece of content has seconds to capture the attention of your audience.