Hello I am having trouble figuring out how to create a black box behind white text for a header. It needs to be able to reach the width of the column which is 3.5625 inches . Its for a large document and rather than creating a thousand black boxes and placing them behind the header, I was hoping there is a style I could apply that would make this less time consuming. Is this possible? Thank you!
If it's a single line of text, a custom Paragraph Rule should do the trick.
What version do you have?
If you work with InDesign CC 2015.2 you can use paragraph shading.
If you work with older versions you need to use Paragraph Rules above and below.