WordPress: How to Delete or Modify Categories
You have misspelled or added a category in WordPress by accident or just decided you want to rename it, but maybe you can’t find where to change the category name. Not a problem, follow this guide and we’ll get you there.
To edit or delete categories, log in to your WordPress administration panel and go to Dashboard → Posts → Categories. There you should see the ability to add new categories, or modify / delete your current ones. You can also see if you currently have posts under those categories. Any posts that are only in the category to be deleted will be reassigned to the “Uncategorized” bucket if you don’t manually reassign them (you can reassign them to a new category after if you wish), as described at the bottom of the Categories page:
Deleting a category does not delete the posts in that category. Instead, posts that were only assigned to the deleted category are set to the default category Uncategorized. The default category cannot be deleted.
The above instructions are based on WordPress version 5.8.