In the Window group, click the View Side by Side button. If more than two documents are open, you'll need to specify which document you want to view in the side-by-side view.

Microsoft Word provides different views of your document, including a two-page layout that resembles an open book. You can also view a page from two different documents for a side-by-side ...

The ability to split the screen vertically and compare two documents side by side in Microsoft Word saves you the eye strain of flipping back and forth between document windows looking for small ...

To enable this view, you need to open at least two calendars in side-by-side view (Figure A). Click the View menu and choose Overlay in the Arrangement group.

So having two documents from the same app side by side is not obvious. But overall, the real benefit of iPadOS 15 in this line is that Apple has made it much, much more obvious what you can do ...