A WordPress widget is an insert that you place in certain areas on your site. You can add them in the sidebars (also called widget areas) placed on your pages.
You can find the list of widgets and the available widget areas by going to the menu Appearance > Widgets. You can also go through Appearance > Customize > Widgets to see the changes live on the site.
Widgets can be easily dragged and dropped into a given widget area.
Each theme creator can place a widget area wherever he wants. And even if this is rare, a theme doesn't have to have one. If you don't find a Widget item in the Appearance menu of the administration, it means that your theme doesn't support this feature.
By default, there are different types of widgets. WordPress provides several ones that include categories, tags, navigation menu, calendar, search field, recent posts, and more. If you drag the “recent posts” widget into a widget area, then it will show a list of recent posts in that area.
Once you have placed a widget somewhere, you will need to set it up. Depending on the widget, several fields will be displayed to allow you to optimize its rendering. They are usually quite simple to set up.
For example, the Text widget has two fields:
- A Title field (which corresponds to the title);
- A Text field (in which you can put whatever you want, even HTML code).
Finally, you should know that you can add other widgets to your site thanks to plugins. This makes it possible to display new things to users. For example, there are plugins to display your latest Instagram posts.
To learn more about widgets, you can check out The Complete Guide to Widgets in WordPress.