The internal links are the links that go from one page on a domain to a different page on the same domain. It means for example in your website your domain name you have one page on this particular domain. Then you want to connect this particular page to another page of the same domain; this is known as an internal link.

But if you want to connect this particular page to another page of another domain. Let us suppose another domain and the page of a particular domain that is known as external. So the linking between these two is known as internal and the linking between these two is known as external.

They are commonly used in the main navigation in your home page. When you see that we have different pages available. Now if you want to connect one page of the same domain to the another page of the same domain in that case we need internal linking. An internal link is one that points to another page of the same website.