My keyboard has split in half what should I do

To easily return the Split Keyboard to the full on-screen keyboard, you can either use two fingers (one on each of the two half-keyboards) and swipe the two halves together - or touch-and-hold the “keyboard” key, then slide your finger to the Merge & Dock option and release.

More information can be found here:

Split and move the keyboard on your iPad – Apple Support

Other related information that may be of interest, concerning the new Floating Keyboard, can be found here:

Use the floating keyboard on your iPad – Apple Support

I hope this information and guidance proves to be helpful in resolving any difficulties.

See this support article:--> If your iPad keyboard is small or split in half - Apple Support

Regards

Giulio