WhatsApp "Delete for everyone" feature allows users to delete sent messages is now being implemented for all users, one week after it has been filtered to select users of the application. The feature allows people to retrieve messages sent on individual chats and groups of WhatsApp, and is available on different platforms, such as Android, iPhone and Windows Phone. One of the most important use cases of "Delete for everyone" function can be when you send a message to the wrong chat or if the message sent contains mistake. It lets people delete sent messages, including media within seven minutes of sending them.
Make sure that you are using latest version of WhatsApp on your phone. The recipient must also have the latest version installed for "Delete for Everyone" feature to work. The messages you successfully delete for everyone will be replaced by "This message was deleted" in the chat. Similarly, if you see "This message was deleted" in a chat, that means the sender deleted their message for everyone.
You only have seven minutes to delete messages for everyone after sending. Once seven minutes have passed, there is no way to delete messages for everyone. Keep in mind that for messages to be successfully deleted for everyone, both sender and receiver must use the latest version of WhatsApp for Android, iPhone or Windows Phone otherwise, it will not work.