how to change to picture background on top header motors theme

how to change to picture background on top header motors theme?

WordPress Customize allows you to setup the general styling of the website visually. In WordPress menu go to Appearance > Customize. Here you can setup most important options of your theme.

See

https://support.stylemixthemes.com/motors-theme-features

For the theme support go here

https://support.stylemixthemes.com/

Hello

How can I change this colored background on the top of the pages?

thanks