You can edit the message-of-the-day file, /etc/motd, to include announcements or inquiries to all users of a system when they log in. Use this feature sparingly, and edit this file regularly to remove obsolete messages.
See Using Your Assigned Administrative Rights in Securing Users and Processes in Oracle Solaris 11.3.
$ pfedit /etc/motd
Edit the text to include the message that will be displayed during user login. Include spaces, tabs, and carriage returns.
$ cat /etc/motd Welcome to the UNIX universe. Have a nice day.