Key board/split

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.

Place your thumb and forefinger on the split keyboard and pull the sides towards each other.

Alternately, tap and hold the little keyboard icon at the bottom right corner, then slide your finger up to select “Merge”.