Important of Interlinking
 

Website owners can tell users and search engines that a particular page or content is important. In this way, site owners can bridge the authority gap between their most linkworthy content and most profitable content. There are many other reasons why internal linking is considered important for SEO.

Interlinking is the procedure of making links within a blog or a website. The other way of linking is inbound linking which means external sources are linking to your website.
One theoretical internal linking strategy of the past was to nofollow most of the links on a page, in order to increase the link juice to a single page. This type of pagerank sculpting doesn't work as an SEO strategy.