By default, some categories of iCloud data, like login credentials and health information, are end-to-end encrypted, while others, like backups, photos, and iCloud Drive files, aren't. To encrypt all iCloud data except mail, contacts, and calendars end-to-end, turn on Advanced Data Protection in Settings (System Settings on macOS) > [your name] > iCloud > Advanced Data Protection. #
TipTuesday support.apple.com/en-us/108756Advanced Data Protection for iCloud offers our highest level of cloud data security and protects the majority of your iCloud data using end-to-end encryption.
Apple Support