FileVault is Apple's implementation for encrypting data on macOS. It encrypts alla data on the hard drive and once activated, it encrypts the data on-the-fly (instantly and constantly) and works seamlessly in the background.

FileVault forces all users to have to enter their password when hibernating or exiting the screensaver. All non-administrator accounts require an administrator to register these users at first login to enable encryption.

The status of FileVault can be read out via the terminal command fdesetup status.