At this time the browser within the IOS platform does not support WebRTC. The Chrome browser uses the inbuilt browser as its back end, so this too doesn't support WebRTC, unlike the desktop and Android versions.
It is believed that Apple will add support for WebRTC into the IOS platform in Q1 2021, but until this is confirmed and deployed, it is unfortunately not possible to use an iPad or iPhone.
To have the best experience, it is better to use a Windows or Apple computer with a larger screen, running a Chrome browser. It is possible to use Mashme from a Chrome browser on an Android device.