Apple has a webpage HERE that lists the new features in iPad OS 15.
QUICK NOTE: jot down notes and drawings
Quick Note is a new feature in iPadOS that allows users to quickly create a new note in the Apple Notes application. Using the Apple Pencil or your finger, drag from the bottom right edge of the screen diagonally towards the center of the screen. When you do this, a small hovering window will appear on the iPad with a new Note sheet.
Using the keyboard on your iPad, you can type a note, but using the Apple Pencil you can begin annotating a handwritten note in the same window. Write or draw with the Apple Pencil, then tap Done. Doing the same action to bring up the Quick Note window a second time will reveal your existing note. If you want to create a new note instead of working with the existing one, simply tap the New Note button in the toolbar. The note will appear in the Quick Notes folder in the Notes application.
Using the Apple Pencil, not only can you handwrite a note, but you can also create lines and shapes that are perfectly drawn. If you draw a line with the Apple Pencil, stop and hold the Apple Pencil on the screen when finished, and the drawn line will become perfectly straight. The same goes for squares, circles, rectangles or other shapes you may wish to incorporate in your note.
Take a screenshot with the Pencil
Instead of pressing Power + Volume Up + Volume Down [on the newer models], you can swipe with the Pencil from bottom left corner diagonally towards the center.
Change Swipe Preferences
You can turn those Swipe options on or off:
Select an option, turn it on or off
Scan anything into Text
You can use Scan To Text in almost any input field across iOS to scan a document and use the text as input. To do this, tap into a text field in iOS or iPadOS 15, then tap again to show the text editing popover. In this popover, select Scan Text.
Once you select the Scan Text option, a camera view will open allowing you to position the camera over top of a document to scan the text. Tap the text in the document that you wish to insert to have the camera focus on that section, then tap Insert to finalize the insertion of the text into the text field in iOS.
Change the size of the text for each App
Users have long been able to choose the text size across iOS through an accessibility feature called Dynamic Type by going to Settings | Display & Brightness | Text Size; however, the text size can now be set on a per-app basis instead of setting it system-wide.
To do this, you’ll first need to enable the Control Center option by following these steps.
Open the Settings app.
Navigate to Control Center.
Add the option for Text Size.
Now open the Control Center while in any app and tap the “aA” button to get a Text Size control panel. Use the slider to enlarge or shrink the text size, and set whether you want this setting for All Apps, or only the one you’re using.
Keep track of what an app is doing with your information [App Recording]
In iOS and iPadOS 15, there’s a new feature that lets you easily record all of the app activity to see which apps request system-level functionality like camera, microphone, internet access and more, and be able to download privacy reports to look at per-device.
To enable the app recording functionality, perform these steps.
Navigate to Privacy | Record App Activity.
Enable the toggle for Record App Activity
Move Safari’s Address Bar
Safari made a drastic change to the user interface in iOS 15. As a result to pushback during the beta testing period, Apple has revamped the design, but it still allows users to decide if they wish to use the old look (with the address bar on top) or the new look (with address bar on the bottom).
You can make this change in Settings | Safari by selecting Tab Bar (bar on bottom) or Single Tab (bar on top). However, you can also make this change in Safari itself by opening the app and tapping on the “Aa” icon in the address bar, then selecting Show Top Address Bar or Show Bottom Address Bar to move it
Drag-n-Drop between apps
iPadOS has long had the ability to drag and drop files between apps, but now this functionality has made its way over to the iPhone with iOS 15. You can now drag and drop a file from one app into another by dragging an image, URL or other draggable data type from one app, navigate to the Home Screen or Multitasking Launcher, open another app, and drop the text, image, URL or other data type. This gesture works just as it does on iPadOS, but does require some talent as the screen on iPhones are much smaller and keeping a single finger dragging the item while the other hand or finger launches another app can be tricky.