The message type sets the icon and sound the recipient sees and hears, and the title becomes the heading of the pop-up. Both sit at the top of the composer, above the message body.

The type combo has four choices:
The icon and sound tell the recipient how urgent the message is before they read a word. Use Info for routine notices, Warning when someone needs to act soon, such as saving work before a restart, and Error for a problem that is already affecting them. Pick None when an icon would be a distraction.
The title field is the heading of the message box on the recipient's screen, shown above the body text. Keep it short and specific so the point is clear at a glance, for example "Server restart at 6 PM" rather than "Notice".
A title is optional. If you leave it empty, the pop-up shows only the body text.