This will show you how to enable or disable ipad split keyboard feature (and also how to reveal the floating keyboard)

• when the keyboard is open, simply touch and hold the key that hides the keyboard.

A menu will pop up with undock and split in it.

• pick split to split the keyboard and undock to make the keyboard float!

You can also ‘pinch to zoom’ the same as zooming out on a photo and the keyboard should split.

turn off ipad split keyboard

To disable the split keyboard, simply hold the same icon in the lower right corner of the keyboard and it will pop up with a ‘Dock / Merge’ selection.

You can also disable the split keyboard option:

Settings > General > Keyboard > Split Keyboard > off

You can also do a ‘pinch to zoom’ the same as zooming in on a photo, and the keyboard will join.

Sources: Apple Support