WhatsApp has end-to-end encryption which ensures the messages stay between the people communicating
There are additional features to stop others from exporting chats, locking and hiding specific chats, and putting the app behind a biometric lock
It’s possible to enable fully encrypted backups and two-factor authentication to enhance security and privacy
Disappearing messages ensures that conversations vanish over time so that even if someone gains access to your phone, they won’t be able to see your recent chats