The Categories widget displays a list of the categories that you’ve assigned to posts.
It helps your readers quickly see what topics you write about.
Here’s what it looks like when it’s added to a blog sidebar:
Only categories that have been assigned to publish posts are displayed in the widget.
Settings
Once you add the widget to your sidebar in Appearance > Widgets, you’ll see that the widget settings look like this:
Title: Allows you to add your own custom title. For example, Posts by Categories.
Display as a dropdown: when this box is selected the months are displayed in a dropdown menu rather than as a list. Using “Display as dropdown” is ideal for reducing sidebar clutter and to save space.
Show post counts: when this box is selected the total number of posts publish for that particular category is displayed next to the link.
Show hierarchy: when this box is selected the subcategories are displayed under their parent if you have used parent and child categories.
Category order
If you want to display your categories in a specific order, you can build a custom menu then add your categories to your sidebar using the Custom menu widget instead.