open “functions.php” file and write the below code in it.
if (!function_exists('hs_setup')) :
function hs_setup()
{
add_theme_support(
'custom-background',
apply_filters(
'hs_custom_background_args',
array(
'default-color' => 'ffffff',
'default-image' => '',
)
)
);
}
add_action('after_setup_theme', 'hs_setup');
endif;