The messages in the Evanesce will be deleted once it is read. In the Netflix show the App is shown as secure and looks like modern mobile application.
This App is totally not real and it only made for the series only. You can only find Evanesce App created by other people in Appstore and Playstore.
It is risky to install such applications as it is not made by the team of the YOU SEASON. The latest YOU SEASON 4 part 2 will be released on 09/03/2023.
The messages in Evanesce App is shown as sent from an unknown number and after reading the message, it will be automatically erased. The Malcolm’s killer uses this app to send information without tracking.