Would I be seeing the Mac screen in a window on the iPad, and controlling the mouse pointer with my finger, or a mouse/touchpad if I have one connected to the iPad?
so: universal control lets you use one set of pointer+keyboard connected to let's say a mac, and when set up properly you can move the cursor off the mac desktop onto the ipad screen, and from then on your mouse and keyboard connected to the mac will be used to move the ipados cursor and the keyboard will input text on ipados. This also allows you to drag files from apps on the ipad to the finder on the mac.
Mind you: this
does not provide you with a way to see the screen of either device on the other one... the ideal use is for when you're on a desk with both devices in front of you. Also I don't think it works with the pencil: you would need to have a trackpad or mouse (and keyboard) connected to either one of the devices.
There is another feature of macos that allows you to extend the mac desktop on the ipad, basically turning the ipad into an additional screen for the mac (which can work as a mirror or as an extended screen). I have no idea if this works in windowed mode on ipados. Also, you would need to initiate this feature on the mac, there is no way around it. After you have your desktop visualized on the ipad, then you can use the pencil as a pointer.
It's important to note that these are two different features and I'm not sure they are intended to work together.
If your specific use case requires that you execute all the work from the ipad, without physical access to the imac (because maybe you want to work on the sofa or whatever), I think the best way would be:
- set up some form of file sharing that can be accessed without problems by both machines (it can be file sharing on the mac or dropbox or even icloud file sharing - for example I have been able to set up shared folders on an external drive on the mac and access the files from the ipad on a local wifi network.)
- set up screen sharing on the mac so that you can use a VNC app on the ipad to log on the mac desktop. in this way you will be able to see the desktop on the ipad and use the pencil or a mouse or a trackpad connected to the ipad as a pointer (not sure whether it works with touch alone);
In this way you would be able to do whatever work you need on the ipad, launch the VNC app and log on to the mac, access the files from the shared location, work on them on the ipad, close the VNC screen sharing and then finish the work on the ipad, without ever leaving the sofa or even being in the same room as the mac.