If you make a typo or regret sending a message, you can undo the action by enabling the “Undo send” option.
This gives you the option to take back a message you just sent for up to 30 seconds. Turn on Undo Send by clicking Settings, and you’ll see a new “Undo” link on every sent mail confirmation. Click “Undo,” and Gmail grab the message before it’s sent and take you right back to compose.
Here’s how to set it up:
With Gmail open, click the gear icon in the top right and then select Settings.
Scroll until you find Undo Send. Check the box next to Enable Undo Send and select a cancellation period from 5-30 seconds.
Be sure to save- scroll to the bottom and click Save Changes.