System messages are a way for you to communicate with your site users on the Dashboard, which is what they see when they first log into the site. Typically, welcome messages, links to user guides or brand guidelines, quick instructions about how to perform an action within the site, your contact information, and more are featured in system messages.
Here's a system message from one of our own sites:
System messages display in the System Message zone on the Dashboard. Users can rearrange the zone's location on their Dashboard by dragging and dropping it within the column.
More than one system message can be displayed, but users will only see the message(s) enabled for their role.
Learn how to create system messages in this article.