Shaking the phone and opening the file in the Trash and moving it back manually are two options
Just about everyone has done it. You want to check your email on the go, so you pull out your iPhone, open the Mail app, open a message, and—oops! You delete it by mistake.
How do you get it back?
There are a couple of ways, according to The New York Times (NYT). If consumers act immediately before doing anything else, they may only have to give the phone a good shake. Upon doing so, an "Undo Trash" alert should pop up onscreen, allowing the user to reverse his or her last action.
Unfortunately, this method may not always work. In these cases, the consumer can restore the deleted message manually. To do this, first open the Trash folder for the correct account. Next, find the email and open it again. A folder icon should appear at the bottom of the screen, which the user should tap to bring up a list of all folders for that specific account. To transfer the email back to the Inbox, simply tap the Inbox icon. Voila!
If users often find themselves accidentally deleting emails when going through multiple notification alerts, it may be a good idea to change the alert style their phone gives them for new mail. To do this, open Settings, and then Notifications. Scroll down to the Mail icon and tap it, then select an account. Users should then be able to choose among the iOS notifications for new mail.