Allow admin to write messages on user dashboard.
You can write a main message, visible to everybody in dashboard widget. You can also write a bunch of messages in different dashboard widget, visible for all users with rights.
Admin can read and write all the messages and setup user roles, who can read and write custom messages.
custom-dashboard-messages
folder to the /wp-content/plugins/
directoryCan i write more main messages?
In default no, because it´s saved in web options, so that´s why there is just one message.