Up to now, I\'ve been including the line for the Apple Touch icon in my head like this:
Since a few of these answers are out of date already, I recommend using http://realfavicongenerator.net/ to generate all the images and markup - I donate a couple euros each time I use it in the hope that it enables them to keep up to date as to what is currently valid on iOS, Android & Windows, so I don't have to.
You can use omg-img for generate all sizes and colors for popular icons. For example:
<link rel="apple-touch-icon" sizes="152x152"
href="https://img.icons8.com/color/152x152/anonymous-mask.png">
This tag returns next image for iOS devices: