I would like to add custom meta tags in order to run Retool apps as a standalone application on iOS (that is, in a new window without the web browser’s UI controls).
<meta name="apple-mobile-web-app-capable" content="yes">
But it is also possible to customize the homepage app icon,
<link rel="apple-touch-icon" href="single-page-icon.png">
Here is a great article on the topic -
Designing Native-Like Progressive Web Apps For iOS