what is the code to add favicon to a file code example

Example 1: html favicon

<link rel="shortcut icon" type="image/png" href="http://example.com/favicon.png"/>

Example 2: favicon for html page

<link rel="icon" type="image/png" href="/favicon.png"/>
<link rel="icon" type="image/png" href="https://example.com/favicon.png"/>