<div class="widget">
Some WordPress widget's code
</div>

register_sidebar( array(
    'name' => __( 'Main Sidebar', 'twentyeleven' ),
    'id' => 'sidebar-1',
    'before_widget' => '<aside id="%1$s" class="widget %2$s">',
    'after_widget' => "</aside>",
    'before_title' => '<h3 class="widget-title">',
    'after_title' => '</h3>',
) );

<div id="sample-widget" style="text-align:center">

// Registering new widget area
function sample_widgets_init() {
    register_sidebar( array(
        'name' => 'Footer',
        'id' => 'Footer',
        'before_widget' => '<div id="sample-widget" style="text-align:center">',
        'after_widget' => '</div>',
        'before_title' => '<h2 class="rounded">',
        'after_title' => '</h2>',
    ) );
}
// Initializing our newly created function named as "sample_widgets_init"
add_action( 'widgets_init', 'sample_widgets_init' );