Check out example codes for "favicon png". It will help you in understanding the concepts better.

Code Example 1

<link rel="icon" type="image/png" href="https://cdn.yourwebsite.com/favicon-16x16.png" sizes="16x16">
<link rel="icon" type="image/png" href="https://cdn.yourwebsite.com/favicon-32x32.png" sizes="32x32">
<link rel="icon" type="image/png" href="https://cdn.yourwebsite.com/favicon-96x96.png" sizes="96x96">

Code Example 2

<link rel="apple-touch-icon" href="older-iPhone.png"> // 120px
<link rel="apple-touch-icon" sizes="180x180" href="iPhone-6-Plus.png">
<link rel="apple-touch-icon" sizes="152x152" href="iPad-Retina.png">
<link rel="apple-touch-icon" sizes="167x167" href="iPad-Pro.png">

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