Chance Miller, 9to5Mac:

For iOS 13, iPadOS 13, and macOS Catalina beta testers, Apple is trying out a new sign-in process for iCloud on the web. When you head to beta.icloud.com on a device running the betas, you can now sign-in to your account using Face ID or Touch ID.

If you log in to beta.icloud.com via a non-beta iOS or macOS, you’ll get the normal login experience, with a 6 digit code appearing that you type in to validate your visit.

If you log in using a beta iOS 13 or MacOS Catalina device, your Face ID or Touch ID verifies you, gives you access, without the code at all. Way better.