Linking a page to another page on the same website is similar to linking to another website, except that you do not need to specify an absolute address. Figure 4.22 shows how it is done. Notice the relative addresses. It means that all the files are in the same directory (folder) as the page displaying the links. See Chapter 2 for explanation of absolute and relative addresses. The main advantage of using relative addressing is that an entire site can be built on a local computer and then uploaded to a Web server for hosting, without having to make any adjustments after uploading, as long as the relationships between the locations of the pages are maintained.
Source: Sklar David (2016), HTML: A Gentle Introduction to the Web’s Most Popular Language, O’Reilly Media; 1st edition.