Notes is a useful app for jotting down reminders, phone numbers or information on your iPhone when you're on the go, but it has limited editing features. However, your iPhone has an Undo function that works in Notes, known as "shake to undo." To access it, get physical with your phone and give it a shake. You don't have all the functionality you get with the Undo command on your computer, but if all you need to do is delete the text you just typed, it'll do the job for you.
Stay in the note you've been working on. If you close it down, your iPhone saves your work, and you won't be able to use the Undo function.
Take a firm grip on your iPhone -- you don't want it to fly across the room when you shake it. Shake it firmly from side to side two or three times to open the Undo Typing menu.
Tap the "Undo" button. All the text you entered in the note in this session disappears. If you change your mind and decide not to cut the text after all, press "Cancel" to return to the note.
Shake the iPhone a couple of times again if you change your mind and want to restore the text you've just deleted. In the Redo Typing menu, tap "Redo" to restore the text.
If you only want to undo some of your recent typing, use another of the iPhone's editing menus. Double-tap on a word to highlight it and then tap "Cut" to delete the word. To delete a sentence or consecutive words, double-tap one of the words, tap "Select" and drag one of the blue selection handles along the line until you've selected all the words to remove. Tap "Cut." You can use this method to edit text that you can't undo in a saved note. This menu also has other editing features, including copy, paste and an option to replace words that you may have mistyped.
Use the backspace function on your keyboard to delete a word if you don't mind doing it letter by letter. Tap the end of a word to position the cursor and then tap the backspace button -- the arrow icon above the return button -- until the word is deleted.
The Undo feature doesn't only work in Notes. You can use it to undo typing in other iPhone apps, such as emails, messages and browser searches.
You can't undo text in stages the way that you can on a computer. On your iPhone, Undo deletes everything you've typed in an open note. For example, if you type two sentences, it'll remove both of them. If you only want to undo one, you'll have to use a different editing method.
Your iPhone doesn't have an Undo function for deleted notes. If you used the trashcan symbol to delete one, it's gone.
Information in this article applies to iPhones running iOS 7. The "shake-to-undo" function works in earlier operating systems but may not work in all apps.