This new feature is perhaps one of the most requested feature on the Facebook-owned instant messaging app, WhatsApp. The ability to delete messages you have already sent; well, the ability to accept or reject being added to a WhatsApp Group is also one of the most requested feature.
The delete sent messages feature will allow you to not only delete the message(s) on your end but also the recipient(s). This feature will be a lifesaver for those embarrassing moments when you found yourself forwarding the wrong (private) message to a WhatsApp Group, and everybody therein started looking at you in a funny way when you meet.
As to just how effective this feature will be, depends entirely on how fast, after sending the message, you delete it. Obviously, the longer you wait the more the chances that the other recipient(s) on the other end will have read the message. If they have read it, deleting the message then will just be doing away with the evidence, but the damage will have already been done. Then again, you never know it the person(s) on the other end did …read more
Read more here:: Finally, you can Delete Sent Messages on WhatsApp