WordPress categories and tags are a way to add an organizational structure to your WordPress posts.
WordPress Categories
WordPress categories are basic ways for you to organize your posts into different categories, such as topics.
For example, when writing a post, think of the wider topic of the post. If you plan to write more posts about this topic in the future, you’ll probably want to group these posts together.
From the post editor page, find the Categories box.
Adding a New Category
If you don’t have any categories yet, click the + Add new category link. Add a new category and click Add new category. You’ll then see your new category has been added to the list of categories.
To assign a category to a post, click the checkbox next to the category.
Another way to manage post categories is through the Posts > Categories link in the WordPress Dashboard navigation menu. Clicking the Categories link will display the Categories page. From here, you can see all your categories on the right, and where to add new ones.
Category Slug
The Category Slug is the URL-friendly version of the category. It is usually all lowercase and contains only letters, numbers and hyphens.
Category Hierarchies
Categories, unlike tags, can be nested into hierarchies. For example, you might have a Jazz category, and under that have children categories for Bebop and big band.
Category Description
The description section is a place for you to add more details about the posts assigned to that category. Some WordPress themes may show this information.
WordPress Categories vs Tags
What’s the difference between categories and tags? Think of your site like a book. Categories are like the Table of Contents and tags are like the terms in the index.