Publish internal news or announcements

I would like to place ads or news, is there a plugin that helps me with this or do they have a way to keep users informed. That is, for a server restart or other types of issues.

Have you tried-out the announcement app?

If so, do I look for it in the app store?

yes, that should always be the first source for available apps:

Is there another form of ads? to appear on the entire screen?
How can I make the notification have sound? It’s active in settings but it doesn’t make any sound.