WordPress’s got one of the most superior Widget systems for adding content to your website sidebars with just a drag and drop!
Managing your Widgets is done through your WordPress Admin panel -> Appearance -> Widgets.
You will see there your built-in WordPress widgets and you can easily drag them from the middle to your sidebar(s). Your WordPress will have a different number of sidebars depending on the Theme you have installed.
In this video below you can see the widget system in action:
