Click on the Presentation link on the main menu, you will find a submenu, now click on the Header Image and Color  link, as shown below.

When you scroll down you will see the current header and it is from here that you change the header in wordpress. You will see a menu card below the header like this one below.

Click Font Color and choose a new color for the font from the available color choices.
Click Upper Color and choose a new upper color from the color picker that appears.
When finished click on the Update Header button.  That’s it! You will notice the header has a new font and upper color. This header will appear at the top of our WordPress site.

To change the header back to the original settings, click Revert and click Update Header button.  That’s it, you now know how to change the header in WordPress.