HTML attributes are located inside an element’s start tag and provide additional about the element.
The example below includes an src and an alt attribute. The src provides the image’s location and the alt provides alternative text to be displayed if the browser can not display the image or read by screen readers.
<img src="sun.png" alt="The sun is a mass of incandescent gas"/>
As you can see from the example above, attributes normally come in key/value pairs. The name of the attribute (i.e. src, alt) is the key and the value is what it is set equal to (i.e., sun.png).