How do I undo my split screen on my iPad?

You can easily manage and manipulate Split and Slide Over views on your iPad. To change a Split view to full screen, place your finger one the centre of the central divider (you’ll see a little grey drag bar) and drag the divider to the edge of the screen - then release; your split-screen view will become full-screen.

You can manipulate other screen views in a similar way. To transform a Slide Over view, to Split Screen, use the grey drag-bar at the top of the Slide Over Window; drag downwards and to towards the side of the screen. As the view changes, lift your finger.

You can also change a Slide Over to a Full Screen view. This time, using the same drag-bar, drag to the top-centre of the screen, then release.

You may find these overview Apple video guides to be helpful:

After viewing, you’ll be ready for the additional Multitasking Guide:

Use Multitasking on your iPad - Apple Support

The iPad User Guide for iPadOS is also a rich source of information. Here are links to both the downloadable and online versions of the Guide:

‎iPad User Guide on Apple Books

iPad User Guide - Apple Support

I hope this explanation and additional information is helpful in resolving any difficulties you may be having with Multitasking features of your iPad.

Put your finger on the middle of the line between the two apps and drag all the way to the left or right, depending on which app you want to be left with.

To undo the split screen or multi tasking view place your finger on the black bar and slide to the direction for the window you want to remove.