Gmail has added another feature. You have experienced lots of new features from Gmail. Now you can undo for your sent emails. It’s called “Undo Send,” and as the name suggests, it lets you take back a sent email, as long as you act quickly enough.

After enable this feature it works like another undo features. When you send an email, you get a message confirming it has been sent, along with a link to “Undo.” This message lasts for 5 seconds, at which point you lose the opportunity to take it back.

Although it is for a short time after email sending like if u sent a mail and forget to attachments or some more information in certain time.