The Announcement widget allows you to type any text to be displayed.
The "Show Announcement" setting allows you to set the widget text source.
If you choose to "enter your own text", the "Widget text" field will allow you just that!
This option, unlike using the text from client announcements and/or client footers, supports the BBCode tags as well as HTML. There is a link to the BBCode reference page where you can check all the possibilities.
If you are using the tags, please make sure that you properly close any open tags. Otherwise, the widget text might not render properly.
The text for Client Announcement and Client footer can be set on the "Client and Form settings" page.
Remember to check a different help article detailing other settings of this widget.