If you often see a pop-up titled “Undo Input” on your iPhone or iPad, it’s because of a feature called “Shake to Undo” which allows you to undo the input by physically shaking your device. Here’s how to turn it off.
First, launch “Settings” by tapping on the “Gear” icon, which is usually found on the first page of your home screen.
In “Settings”, tap “Accessibility”.
In the next menu, press “Touch”.
On the “Touch Settings” screen, scroll down until you see a switch labeled “Shake to Cancel.” Press the switch to turn it off.
The next time you shake your iPhone or iPad while typing, you won’t see an “Cancel Typing” pop-up.
Two alternative cancellation methods on iPhone and iPad
If you’ve turned off “Shake to Undo” and still want to be able to undo the typing on your iPhone or iPad, you’re in luck. Starting with iOS 13 and iPadOS 13, there are two new ways to undo text input on iPhone and iPad it does not involve shaking your device.
Press to cancel: Double-tap three fingers on the screen to cancel the entry. In some applications, the text you just entered disappears. In others, you may see a pop-up on the “Cancel” button that you need to press for the cancellation to take effect.
Swipe to cancel: Swipe left with three fingers on the screen to cancel the entry. Just like the “Tap to Cancel” feature, some apps will immediately erase what you typed last, and others will present a “Cancel” pop-up button. If so, tap it.
Good luck and good editing!