If you are looking to permanently delete WhatsApp messages after three hours, there are a few steps you can take. First, it is important to note that if the message has already been seen by the other party, or was sent in a group chat, it will not be possible to delete it from both sides of the conversation. However, here are some steps you can take to ensure your messages are deleted as soon as possible:
1. Enable Auto-Delete for Messages: Go into your WhatsApp Settings and select “Account > Privacy” and then choose “Auto-Delete Messages”. You will be able to set a timer for any message that is older than 3 hours from being automatically deleted from both sides of the conversation (provided they have not yet been read).
2. Manually Delete Sent/Received Messages: If you do not want certain messages stored on either side of the conversation for more than 3 hours, manually deleting them is an option as well. To do this, simply long press on each individual message within a chat window and select "delete" when prompted - this will only delete that specific message; however, keep in mind that if it has already been read by someone else they may still have access to its contents until their copy is also manually deleted or auto-deleted depending on settings enabled within their account's privacy tab.
By following these two methods you should be able to ensure your messages do not remain visible after three hours – granting yourself peace of mind knowing conversations won't linger around longer than intended!