INTRODICTION :
Hello Friends Many times when we send our emails to recipients, there may be you forgot to add some important texts or forgot to add attachments or attached wrong files.
At that time it's very embarrassing and forcely we need an undo tab. Because that may leave a bad impression on your recipients whoever is that. But Dont Worry I Have Trick To Bypass iT. This is not any hidden trick or third party application, it's just a gmail's feature, which I'm going to share with you today.
STEPS :
1) First Login in to your gmail account.
2) click On the gear icon Top right of the gmail and select settings option from the drop down list box.

3) Now click on Labs tab in the settings page.
4) Find undo send option and enable it.

That's it. Now it's your turn to apply this gmail's feature and be safe while sending emails to anyone.