Split on screen keyboard

1. Go to Settings > Keyboards > turn on Split Keyboard
2. Now hold down the key (on the bottom right) and select Split.
3. To merge them back, hold down the same key and select Dock and Merge.

See >>> Split and move the keyboard on your iPad – Apple Support

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.

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