What theme are you using? Where did you download it from?
You can use the following css rule
.navbar{background-color:<<your color >>;}
Hi Esmi – The theme was compose WP, it was already installed when I installed WordPress.
Hi MrTom414 – Thanks I will try this.
Hi MrTom414, I tried this css rule. I inserted into the child theme using editor. It still hasn’t changed the colour. Am I doing something wrong when I am editing the CSS?
Try asking in the theme’s dedicated sub-forum:
https://wordpress.org/support/theme/compose-wp
The theme’s developer may be able to help with this & any other questions relating to the theme itself.