What happens is that each operating system works with the Icon in one way. Usually what you see is Favicon being turned into the shortcut icon on mobile devices.
What I tell you is to use a Favicon generator that also has the JSON Manifest, and generates icons for all operating systems. Here is an example. of this type of site. It will give you a pack of images and script and vc will index on your page inside the <head>
https://realfavicongenerator.net/
Example code for you to put the shortcuts using favicon, remembering that this code must be inside the <head>
document and the images of this example at the root. OBS: the images will be generated by the mechanism of the site I mentioned as an example, but there are other...
<link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png">
<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png">
<link rel="manifest" href="/site.webmanifest">
<link rel="mask-icon" href="/safari-pinned-tab.svg" color="#5bbad5">
<meta name="msapplication-TileColor" content="#da532c">
<meta name="theme-color" content="#ffffff">
Do you refer to the favicon at the top of the site ? Do you want when you save this link to the phone it appears this icon is it ?
– Mike Otharan
That’s right Mike, in my case he gets the letter D on the icon, and has the favicon on the page, including I looked at the source of facebook and other sites that have to see if I was stating right and at first it was the same, but in mine does not work
– Rafa
Use this code on your website <link rel="shortcut icon" href="pathfile/favicon.ico" />
– Mike Otharan