One of the marquee features of macOS Sonoma is widgets on the desktop. The widgets can come from Mac apps, just as they could before in previous versions of macOS, where they appeared in Notification Centre. New to Sonoma, they can now also come from select iPhone apps running on your nearby iPhone.
This is a pretty cool and useful feature, as it goes, for those wanting it, but when it was announced there didn't appear to be a way for a VoiceOver user to use it. At some point, Apple fixed it without telling anyone and, though it's still not documented anywhere as of time and writing, there's now special support in VoiceOver for dragging widgets onto your desktop. Personally, I've found it to be of limited utility, and I wouldn't miss it if it were gone, and of those I've tried, I'm mostly interested in using widgets from the Mac rather than iPhone. Still, I can imagine that it could fill gaps for easy access to information for people who appreciate it. Here's how to use it.
Before we begin, make your desktop the foreground by pressing VO-Shift-D, then open Notification Centre by pressing VO-O. (VO is the VoiceOver modifier, which can be caps lock and/or Control and Option, depending on how you've configured this option.)
Next, press the Edit Widgets button to add or edit widgets. This will be the last item in this view, so you could press VO-End (VO-FN-Right, on laptops) to reach it.
Next, find the widgets from the app you're interested in. There's a search box which you first land in, allowing you to filter by the app's name, and, adjacent that, a group with radio controls for each app that's installed on your Mac and iPhone, which restricts the view to the widgets for that app. By default, you see suggestions for possible widgets to add when the "All Apps" button is selected, but I recommend filtering the list to get a complete idea of what's available as well as all possible widget sizes. If you notice duplicates in the list of apps, that's probably apps on your Mac and iPhone that appear separately, but normally if you select an app for which both Mac and iOS widgets are available, there will be a further control to scope the widgets by that platform.
Now, check out the available widgets. If you're not already in the "Previews" grid, interact with it. If you can't seem to find it, try tapping Tab a couple of times and then locating it again. You should be able to identify each widget available, in all possible sizes. If you're lucky, interacting with one gives you some idea of what information is contained within the widget; sadly, more often than not, you only find the add button. We'll come to that button later, but the bad news is that sometimes, only trial and error will tell you which widgets are actually useful to you. The good news is that you get the same information regardless if you use a desktop widget or a Notification Centre widget, so it's not too disruptive to try it by adding it to Notification Centre first, to see if the widget would be helpful to you, before putting it on your desktop.
Finally, let's add a widget. When you find the widget in question, if you interact with it, there's an add button. This is not the one you want to add the widget to your desktop; instead, this adds that widget to Notification Centre. This is because you have accessed this view from Notification Centre. When you access this view from the right-click menu on the desktop, this button adds the widget to the desktop, but as far as I can tell there's no way to access the right-click menu of the desktop with VoiceOver. So, instead, rather than interacting with the widget, simply press VO-Space, to activate the widget. This triggers VoiceOver's built-in automatic widget dragging functionality. You can achieve the same thing by pressing VO-Command-Space to open the actions menu and, from there, choose "Drag to Desktop".
Now, check your handiwork. Once you hear the sounds of dragging and are told that the widget is inserted, press Escape a couple of times until you are back on your desktop. Navigate it until you find the widget you just added, interact with it, and examine the contents. If you're happy, you're done. Otherwise, you can try to modify the widget by pressing VO-Shift-M, to open the shortcut menu, once the widget is selected, in order to change its size, or remove it altogether. Depending on the widget, there may also be settings for the widget itself, which customise what's shown; in this case, there'll be a menu item called "Edit Widget Name ...", where Widget Name is the name, and interacting with the widget now shows you a view for editing. "Weather" is a widget that has this feature.
There are a couple of other things to note.
First, there's the Item Chooser in VoiceOver, accessed by pressing VO-U. On the Desktop, if you open the item chooser, one of the types is widgets. Press VO-left or VO-right to choose the widgets setting, VO-up and VO-down to select a widget, and VO-space to move the focus of VoiceOver directly to that widget.
Next, there's a bunch of system settings, accessed from the Apple menu, that pertain to widgets. They're under Desktop & Dock, under the Widgets heading. You can choose whether widgets appear at all on your desktop or in Stage Manager, what colour scheme they should use, and whether your iPhone widgets are included. Your iPhone has to be signed in to the same Apple ID as your Mac, and be sharing the same network.
Finally, I observe that the accessibility and reliability of widgets is something of a crap shoot, to be honest, and especially when you get iPhone widgets involved. The Mac has never really needed widgets, since there are so many other ways to get rapid access to information, like the menu extras in the menu bar, AppleScripts that talk through VoiceOver, and so on. It might be that, actually, there's a better and more reliable way to do what you want than the use of widgets, especially if you've got some coding chops.
I hope this has helped you make use of what is a pretty cool and important feature of Sonoma, faults notwithstanding.