Hello @macsuibhne,
Thank you for reaching out,
First, check if the widget itself has an option to set a background (color or image). If it doesn’t, you can add a background using custom css: https://ibb.co/23xY1g0q
For example:
#wrap .wp-block-heading {
background-color: #f2f2f2 !important;
color: #212121 !important;
}
or:
#wrap .wp-block-heading {
background-image: url('https://example.com/your-image.jpg') !important;
background-size: cover;
background-position: center;
color: #212121 !important;
}
You can add this CSS under Appearance > Customize > Additional CSS.
I hope it helps,
Best Regards