OpenSSH is a fee open source set of security-related utilities based on the Secure Shell (SSH) protocol that runs on Linux and other operating systems. Microsoft has made available OpenSSH for Windows (Beta version) as part of the Windows 10 Fall Creators Update and Windows Server 2017 version 1709. Microsoft does not recommend using OpenSSH for Windows in production environments while it is still in Beta.
To install OpenSSH for Windows, select the Start Button –> Settings –> Apps –> Manage optional features –> Add a feature –> OpenSSH
A reboot is required after installation to enable this feature.
BleepingComputer.com has extensive instructions on how to configure OpenSSH Server for Windows (Beta).
Update: OpenSSH is now fully available as part of Windows 10 April 2018 update version 1803.