Hello,
Thank you for reaching out to our support team.
You can update the Header by going into your WordPress admin -> Appearance -> Customize -> Design -> Header -> Background.
To update the footer color you can go into your WordPress admin -> Appearance -> Customize -> Design -> Footer-> Color.
If you are using templates for your header and footer you will have to update the templates for each. Here is a guide on how you might accomplish this Update Header Templates.
Thanks
Elana D.