How to Add a Custom Sidebar to a WordPress Theme? What’s a sidebar in WordPress ? WordPress Sidebars allow you display all type of widgets inside your theme. And you can use “sidebars” to display widgets anywhere you want.All themes by default come with at least one sidebar in it. Sidebar is one of the most used Requirements For many developers. For adding sidebar we will use one hook and one WordPress function. widgets_init hook register_sidebar function About “register_sidebar” register_sidebar( array|string $args = array() )   It will returns the sidebar ID. Parameters ‘name’ (string) The name or title of the sidebar displayed in the Widgets interface. Default ‘Sidebar $instance’. ‘id’ (string) The unique identifier by which the sidebar will be called. Default ‘sidebar-$instance’. ‘description’ (string) Description of the sidebar, displayed in the Widgets interface. Default empty string. ‘class’ (string) Extra CSS class to assign to the sidebar in the