How to change the page title/headline
The orange title at the top of the content area for each page is the headline.
By default, the headline is the page title. So you can change it by changing the page title.
Make the headline different from the page title
If you want the headline to be something different from the page title (most common on department home pages), go to the editor interface for that page, add the custom field “headline” and put your new headline text in the Value field.