Access to the site below and download OpenSSH. Generally on Windows 2012R2, choose [OpenSSH-Win64.zip] to download.
⇒ https://github.com/PowerShell/Win32-OpenSSH/releases
[2] Extract ZIP file and move the extracted folder to any location you like.
[3] Open [System Properties] and click [Environment Variables] button.
[4] Select [Path] in [System variables] section and click [Edit...] button.
[5] Add OpenSSH folder PATH you located in [Variables value] section. After adding it, Close [System Properties] window.
[6] Run [Powershell] and move to OpenSSH folder you located. Next, run a command '.\install-sshd.ps1' to install sshd service like follows. If successfully message is shown, it's OK to install.
[7] Next, Generate SSH host-key. Run a command '.\ssh-keygen.exe -A' like follows.
[8] It's OK to install sshd. Next, Open [Services] and start sshd. And also change to [Automatic] for [Startup Type] like follows.
[9] If Windows Firewall is running, add 22/TCP port to allow SSH connection.
[11] For connecting from other device to Windows Server open CMD and type Administrator@192.168.1.2 (server IP address)>
More information: https://www.server-world.info/en/note?os=Windows_Server_2012&p=openssh