Similar as what you can do on linux with the Message Of The Day (MOTD), there is a way to display a message to users when they login to their session.
Microsoft refer to this as a “legal notice” and can be achieved through the registry.
1. Open the Windows Registry Editor with elevated privileges :
regedit.exe
2. Browse to the following key :
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System
3. Double-click on “legalnoticecaption” and write the notice title
4. Double-click on “legalnoticetext” and enter the content message of your notice
You are all set!