In Whats App on iOS, go to Settings>Account and at the bottom there is a slider called ‘Share My Account Info.’ Unchecked that if you don’t wish for Whats App to share your information with Facebook. Whats App says if a user picks ‘Don’t Share’ they won’t be able to change it in the future.
Users need only a phone number to sign up for Whats App. A Facebook account isn’t required. Whats App said users who signed up as of Aug. 25 have a 30-day window to opt out of sharing some account data with Facebook after accepting the new terms of service. The app rolled out end-to-end encryption earlier this year.