Gmail’s “Undo Send” feature has been around for some time, but it’s one of those things that people don’t think about activating until they’ve sent an email that was a little embarrassing.

  1. In the upper-right corner of the screen, select the gear icon and then click on Settings, which will take you to the Settings window.
  2. Under the General tab, scroll down until you see Undo Send. Click the check box to enable the feature. Choose a cancellation period of between 5 and 30 seconds.
    Scroll to the bottom of the General tab and click Save Changes to activate the feature.
  3. To test Undo Send, compose an email and click the Send button.
  4. At the top of the screen, you’ll see the option to “Undo” after the sentence, “Your message has been sent.” This will prevent the message from going out if you act within the cancellation period.