All of the fonts in San Francisco font family, developed by Apple. Including the new serif fonts found in the Apple Book app on iOS 12.
Compatible with Windows.
For SF Hello font, currently it is impossible to obtain it can be obtained only if you are an Apple employee or an authorized Apple reseller.
Apple fonts are not meant to be used for commercial purposes outside Apple products.
For the SF Mono typeface, you are allowed to use it only in Xcode, Terminal.app and Console.app.
For the SF Serif typeface, your use of the Serif font is subject to the terms of the applicable iOS/macOS/tvOS/watchOS Software License Agreement.
This is a rare typeface that only appears in internal Apple presentation PDFs, unfortunately it is subset embedded so the full font data cannot be extracted. In order to obtain SF Hello, you must be a member of Apple Sales Website - which is impossible for regular users.
MDN web docs for the font choosing demo code.
This website demonstrates the font family owned by Apple. Website template designed by templatemo. Repository maintained by TheLionCape. Forked from now deleted repo by Windy Boy.