Usually it happens that we sent an email to wrong email id, means we share a important information to wrong person.
To avoid this mistake gmail has a function called recall option.
If you want to recall a sent email in gmail then follow the below steps.
Step 1: After login into your gmail account, go to the setting option available in the right corner of your screen.
Step 2: Click on the setting and then scroll down. You will be able to see "Undo Send" option. Hit the click on checkbox.
Step 3: Now below "Undo Send", there is one feature called as "Send cancellation period". Select the option as per your requirement. In other words, the time limit you will have to hit undo.
Step 4: After making the required changes in the setting, save the changes. Gmail "Undo Send" feature is now enable.
Step 5: Now when you send an email you will the "Your message has been sent" box with an additional Undo option. Hit Undo within the time limit and the person will never know you sent it.