This Add-On sets the Application Icon and Splash Screen Icon as Apple Touch Icons.
In older versions of iOS, when a website is added to the home screen, a screenshot of the page is used as the icon unless your website specifies the icons.
This add-on fixes that by specifying your app icons as Apple Touch Icons.
Navigate to SuperPWA > Addons and activate the Apple Touch Icons add-on. The Application Icon and Splash Screen Icon that you have set in SuperPWA > Settings will now be used as Apple Touch Icons.
There are no settings for this Add-On, hence no user interface in the WordPress admin.