Set a startup message
- Open the Microsoft Dynamics AX 2012 Configuration utility. In Windows, click Start > Control Panel > Administrative Tools > Microsoft Dynamics AX 2012 Configuration.
- Click Manage > Create Configuration.
- Enter a name for the configuration and then click Active configuration.
- On the General tab, in the Startup message box, type the message you want to be displayed, and then click OK.When the client is started, the text is displayed as a message that includes an OK button.
Open As Administrator
and then you can input your massage as needed in right highlighted box as show in the screen shot: