Definition and Usage
For <a> and <area> elements, the href attribute specifies the URL of the page the link goes to.
For <base> elements, the href attribute specifies the base URL for all relative URLs on a page.
For <link> elements, the href attribute specifies the location (URL) of the external resource (most often a style sheet file).
Read on about the href attribute in this tutorial: https://www.w3schools.com/tags/att_href.asp