How to undo send mail in gmail ?

You all use Gmail for email service but here i am going to write about a cool feature of Gmail. I am sure you don't know how to undo send in Gmail. Gmail has a feature by which you can do it but by default this is disable and you have to enable it for use.


First go to gmail labs(setting -> labs)
and then scroll down the page 

Now enable this feature.

After doing all this, You enabled this feature to your gmail account.

send an email and now you will get undo option after sending any email.

try and enjoy