When you install WordPress, WordPress will have 1 default post, 1 standard comment, and 1 default category. This category is called Uncategorized. Unlike the posts and comments this category cannot be deleted as it serves a very special purpose.
When you write an article and forget to select a category which is a common mistake, WordPress automatically selects the Uncategorized category for the published articles. So not only that it is shown in the URL Structure, but also adds a category among other categories.
This is something you really need to consider when running a professional site and having the Uncategorized category appear due to a minor human error namely Forgotten. In my opinion, this causes a minor blot on the reputation of a blog editor. Often times this happened by mistake, and some people considered him a sloppy editor.
To overcome this, all you have to do is rename the Uncategorized category or delete and replace it.
Rename or Change Uncategorized
To change the name of the Uncategorized category, go to the menu Post »Categories, Click Edit on Uncategorized and please change Name and Slug, For example “WordPressAnd click the button update.
Now if you forget not to choose a category when you publish an article, the article will automatically have or select a category “WordPressAs the default category.
Delete or delete uncategorized
To delete the default category, we really can’t, we really have to create and select a special category in WordPress for us to set as the default, and after that delete the category Uncategorized, First you create a category on the menu Post »Categories and create a default category for example “WordPress“.
After that you enter the menu Settings »Writing, And replace Default Post Category from Uncategorized to WordPress. If you have changed the default category, now you can go back to the category menu and delete the category Uncategorized.