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, and more to come.
Can be opened on 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 SF Pro, its license can be found here.

For the SF Mono typeface, you are allowed to use it only in Xcode, Terminal.app and Console.app.
For the SF Serif, SF Compact (Rounded), SF Pro Rounded, SF Cash and SF Shields typeface, your use of this font is subjected to terms of the applicable iOS/macOS/tvOS/watchOS Software License Agreement.
For the SF Hello typeface, it is restricted to Apple employees and permitted contractors and vendors.

Every font in this repository belongs to Apple. The purpose of this repository, and its website, is to demonstrate the San Francisco font family, and under no circumstances is it used for commercial purposes.

You can visit https://windyboy1704.github.io/San-Francisco-family/ to try out the fonts. Please note that several new fonts are not yet available on the website.

This is a rare typeface that only appears in internal Apple presentation PDFs, unfortunately it is subset embedded so I cannot extract the full font data. In order to obtain SF Hello, you must be a member of Apple Sales Website - which is impossible for regular users.

Copyright © 2016-2017 Apple Inc. All rights reserved. Use of the SF Hello font is restricted to Apple employees and permitted contractors and vendors and may only be used for the purpose of creating Apple-produced communications.
Due to its license I am not able to upload the font here.

MDN web docs for the font choosing demo code.