Article by Domain Support
Gmail Undo Send is a very useful feature that has been around for several years. It was announced March 2009 as an experimental feature with Google Labs. Android, Chromebooks, and Chrome for Windows and Mac officially launched Undo Send in June 2015. It was released on iOS in November 2016. We have all clicked the send button on an email that we later regretted. If you catch a mistake or realize you’ve left something out within 10 seconds of sending, Gmail lets you Undo Send. You don’t have much time, but those precious ten seconds could prevent an embarrassing or unprofessional email from being sent. Gmail lets you extend this delay in sending to a maximum of 30 seconds.
Un-sending an email is not so easy in other mail programs. Microsoft Outlook has Recall This Message that works if the recipient also has Microsoft Exchange, which is often not the case. There are other caveats such as if the recipient has the preview pane enabled he/she may still be able to read the recalled message. There are programs that you can purchase to enable this undo send feature, however Gmail is currently the only email provider to offer it within the app, free of charge.
Simple for iOS
Use the Gmail App from the App Store. Just be sure Undo Send is enabled. After you create an email and click the SEND button (near top right corner little blue arrow button) then at the bottom of the phone you will see SENT on the left lower corner and in the right lower corner you will see UNDO. You have five seconds to undo your message before it is gone forever to your recipient. Here are the official instructions from Google.