Definition of a hyperlink.
When you surf the Internet you use these links (usually in blue on your browser) and when you hover the mouse over them the pointer changes (the mouse pointer usually changes from an arrow to a hand).
What is a hypertext link for?
This hyperlink usually points to another page on the site or on another site. But it can point to documents, music, videos, …
The hyperlink therefore contains a reference to what is called a URI (Unique Means of Identifying a Resource on the Internet). There cannot be 2 different pages or 2 documents with the same URL.
Benefits of hyperlinks
Hypertext links move quickly from one page to another: we say surf (hence the expression surf the Internet).
You don’t need to ask for permission to add a link that points to an outside site or to a resource that doesn’t belong to you. (be careful, if this resource is protected by rights, you must however be vigilant).
Search engines rely on these links to search and rank the sites they crawl. Indeed, when a search engine starts on a page of a site, it will explore all the URIs (content on this 1st page). It will then do the same by exploring all the URLs it will have found on the following pages, and so on. Ultimately, it will have crawled and indexed the entire site if the pages it contains are at least referenced once.
Hyperlinks are easy to use and do not require any knowledge, they have contributed to the success of the internet.