In Windows 10 Redstone 5, PC users will soon be able to enable Windows 10 in S mode just as easily as the feature can be disabled.
Although Microsoft has made it easier to switch off Windows 10 S mode on a device running Windows 10 Home or Pro, there is no easy way to switch S mode on. The only way to do it right now is to either buy a device with Windows 10 S mode enabled out of box, or create new installation media that has the S mode switch enabled. There's no in-OS switch to enable S mode.
All of the Windows 10 S devices you can buy right now
Full story from the WindowsCentral blog...