Gmail has activated the ‘Undo sent’ email option for users in the default settings. The Gmail ‘undo’ sent email option was already available as part of the Google Labs tool since 2006. Users who had activated the feature in the Lab options will find that it is already activated for them. For other users, they will have to go to settings in Gmail and they will see an option to turn on email undo. You can choose a timing as well. However the Gmail Undo feature is not available for companies that are using Gmail are their company email.
