When I first noticed this multi-profile thing on Chrome OS code, I thought it is going to be something like you switch accounts on your PC or Mac. You have two or more users logged in to your computer, and you switch between them entering password each time you switch.
But looks like Chrome OS has a slightly different implementation of this feature. I think it is similar to the multi-profile arrangement you have within your Google account. Once you authorize and configure an account inside another, you switch between them with ease, not password required.
It is something similar here. Take a look at this demo video from François Beaufort:
How To Test Chrome OS Multi-Profile Switching
You should be on the development channel of Chrome OS to try this. Once there, enable this flag and restart your Chromebook.
Before you start, please note that this feature is in the early experimental stages, (hence dev channel only, behind a flag!) and you will see a lot of bugs and issues along the way.
You can start to run multiple profiles in your signed-in session by clicking on your profile picture in the system tray popup, selecting “Sign in another account”, and choosing from the list of profiles you had previously added on your device.
I do not know if it is expected/planned, but you cannot add a new account using this screen now. You must have an account added and set up to connect.
Switching profiles is as easy as clicking on the profile picture in the system tray popup. But there is a keyboard shortcut as well. <Ctrl> + <Alt> + <Period> and <Ctrl> + <Alt> + <Comma> keyboard shortcuts.
You can move windows to different profiles with a simple right click in the window top bar. As you can see in the video, even the Files App even supports this feature, explains François Beaufort.
This is an exciting new feature for Chrome OS, one that will make in to one of those short videos. How will this feature evolve while it makes its journey through beta channel to stable channel is something that I am curious about.