February 08, 2012, 5:24 PM — Here's how you can quickly undo or redo typing on your iPad.
1. Bring up the on-screen keyboard on your iPad.
2. Tap the .?123 key.
3. You'll see the "undo" key appear.
4. Just do the same thing again if you need to use the "redo" key.
For more, see the original article at the link below.