Open Gmail
Click the gear icon and select See all settings
Under General, find Undo Send
Set the cancellation period to 5, 10, 20, or 30 seconds
Scroll down and click Save Changes
After sending an email, click Undo in the bottom-left corner before the time runs out
If the undo period has passed, the email cannot be recalled in Gmail
If needed, send a follow-up email to correct or retract the message