Since WhatsApp introduced the "Delete for Everyone" feature back in November 2017, the recipient can understand that a message has been deleted as there is a prompt in its place with the "This message has been deleted" tag.
As of now, it is being tested on Android devices, but if the previous testing pattern is taken as any indication, iOS and Windows versions may also get the adaptive icon shape feature, but only after testing. To be precise, one hour 8 minutes and 16 seconds, beyond which, the user can not erase messages.
Who can use this feature?
The latest version of the WhatsApp beta app can be found in the Store here.
Recipients may see your message before it's deleted or if deletion was not successful. The post points out that this will make sure no-one can illegally delete messages older than 24 hours for everyone. With this, iPhone and iPad (LTE) users will be able to delete unintended messages from group chats after more than an hour. The time limit is 24 hours rather than 1 hour to account for phones which are offline when the Delete for All message is sent. It has also been pointed out that if someone replies to a message in a group, and the same is later deleted for everyone, the message continues to show on the group.