Updated: Apr 8
WhatsApp have the following two options to delete the message
DELETE FOR ME - This options allows you delete your message that you sent or received from some one. It also have the option to delete the multiple message at a time. But it will not make any impact in receiver side, still they can able to see message which they sent or received.
DELETE FOR EVERYONE - In order to delete the message to both sender and receiver we need to choose delete for everyone option. Message which you successfully deleted will be replaced by "This message was deleted" in receiver side. It is very useful at the time when you mistakenly sent the message to someone. But you can delete the message within 7 mins of sending it.
How to read this deleted message
According to the report we can read the deleted whatsapp message which is still on the device and can be access through android notification log feature. There are plenty of application in playstore to read the device notification logs. I have used this application.
Once you install the application then you must enable the permission for notification reading. Then you can able read your deleted messages.
But this feature not available for iPhone users. Because in iPhone, there is no application for read notification history.