Check out example codes for "add icon to website tab". It will help you in understanding the concepts better.

Code Example 1

Convert your image to .ico (use https://hnet.com/png-to-ico/)

Rename your ico to favicon

add this to the <head>: <link rel="shortcut icon" type="image/x-icon" href="favicon.ico" />

Code Example 2

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

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