function minduo_widgets_init() {

    register_sidebar([
        'name' => __('Footer Widget 1', 'minduo'),
        'id' => 'footer-1',
    ]);

    register_sidebar([
        'name' => __('Footer Widget 2', 'minduo'),
        'id' => 'footer-2',
    ]);

    register_sidebar([
        'name' => __('Footer Widget 3', 'minduo'),
        'id' => 'footer-3',
    ]);

    register_sidebar([
        'name' => __('Newsletter', 'minduo'),
        'id' => 'newsletter',
    ]);

}

add_action('widgets_init', 'minduo_widgets_init');