If your smart keyboard clicks your nerves, it may be nice to turn it off. Either a while, or forever. There are actually three ways to do it.
The easiest way to temporarily silence your phone is to turn off the mute switch on side of the phone. It will immediately silence the click. It also gets all the other sounds to silence, except music and anything that you start.
With Ipad this can work, but only if you have a model with side controls actually set to be mute button and not rotational lock. You can set it in Settings -> General -> Sidebar Function .
The second way to get rid of the sound is to simply lower the volume. The keyboard tab uses the same volume as other sounds (except for alarms and ringtones that have a separate setting). Use the volume buttons on the page or volume control in Control Center and lower to a level when you no longer disturb the click.
Turn off the click sound only with Settings
If you never want to hear the click again and do not want to affect the volume, you can do it in Settings -> Audio and Haptics . At the bottom of the different signal settings, there are two controls for Keyboard Sound and Locking Sound.