https://thenextweb.com/apps/2019/10/02/whatsapp-is-testing-a-self-destructing-feature-for-your-secret-chats/

Several popular messaging apps such as Facebook Messenger, Telegram, and Signal offer a “self-destructing messages” feature. You can set a timer for messages in your conversation with someone, and those will disappear after the specified time.

This feature might soon be coming to WhatsApp. According to a report by WABetaInfo, the company is testing disappearing messages on its Android app’s test version 2.19.275.