Hi,

You should paste this code into the function.php of the child theme or via the CodeSnippet plugin here: https://wordpress.org/plugins/code-snippets/

add_filter( 'get_template_part', function ( $slug, $name ) {
    if ( ( is_single() || is_page() ) && $slug === 'template-parts/footer/footer' ) {
        return false;
    }
    return $slug;
}, 10, 2 );

Regards,
PenciDesign.