Unless you are a tech genius (in which case respect! and please do not read on), you probably pulled your hair out not once when accidentally deleting something important or replacing it by pasting in the Notes, Mail or any other app on iPhone. And let’s be honest, iPhone’s touch keyboard has tiny keys, floating menus appear out of nowhere and move around unpredictably, so to me this happens a lot. Before I just lived with it (and pulled my hair out), wondering why I have Undo button on iPad but not iPhone. Recently I researched it and learned that there is a simple trick – when you make a mistake and want to undo your latest action, shake your iPhone and an Undo menu will pop up. But you have to stay in the same application, switching to another one will render Undo function inactive. Here you go. Hope it helps.