The Header can be set to be transparent instead of having a color background. It can set to be transparent globally (on all page) or just in some of the pages of your choosing. To start working with that, open up the Customizer and navigate to Header > Header Transparency.
Default Color Scheme (Light/Dark)
You can choose to define two color schemes, a light and a dark one and you’ll be able to use one or another in different pages, based on the content you got there. This helps you avoid situations in which you’d have white text over a white background.
For example, if most of your pages are white / light background you would choose the Dark as the default, to make sure you’ll get black text over a white background. That’s just an example, the black could be any other color.
How to choose a different header color scheme for a specific page?
You can set up page specific exceptions for the color scheme used by the header, by simply choosing a different option from the dropdown available in the Page Options box.
If you have troubles finding this, navigate to Screen Options and check Page Options.