How to quickly undo a typing mistake
It is an everyday occurrence to make an error typing on the iPhone, but hitting the delete key to remove letters one by one is somewhat tedious. For help with this, shake your iPhone, so you can quickly "undo" your typing!
When you have made a typing mistake:
You have made a typing mistake!!
But that is not so unusual while you are typing on a smartphone. Then, what you can do is...
Shake iPhone
Shake your iPhone to undo, in any way from side to side or up and down.
Tap the [Undo] button
The [Undo] button will appear on the screen, and simply tap it to delete your typing.