Keys and popups
How tall the keys are, how round, how far apart, and what happens on screen when you press one.
Clink for iOSSize and spacing
Settings path: Home Keys
Size controls adjust the keys, while spacing controls adjust the gaps around them. In Android test builds, the live preview follows width, height and spacing as you drag. Drag back to the starting value to restore the previous size.
Taller keys are easier to tap accurately. Shorter keys give more screen room.
The gaps around the keys, set apart from their size. Square keys with tight spacing is the classic mechanical look.
Key shape
One slider takes them from fully rounded to square-edged.
One slider covers the whole keyboard, so the letters, the space bar and the return key stay in the same family.
Key popups
Settings path: Home Popups
The bubble above the key you press. Keep it, turn it off, or set how it springs.
Turn it off and nothing else changes: the key still registers, and the letter still lands.
Motion
Settings path: Home Motion
Motion is the press itself: how a key responds under your finger, and how quickly it settles afterwards.
Hitboxes
Adaptive hitboxes grow the keys you're likely to type next and shrink the ones you aren't. Nothing moves on screen, so you never see it happen.
Settings path: Home Hitboxes
The Hitboxes page holds that behaviour, along with the size of the target around each key, which is not the same thing as the size of the key you can see.