On the left side above the settings options and just below the dashboard option, you can find the menu named as post. There are several sub-menu setting options in it such as add category, edit category, delete a category, and arrange category. As it is clear from the name, it's not too difficult to understand the functioning of this sub-menus. 

Add category 
Categories are simply the type of your post. At the very first, you get the option to add a category to your post. As I said earlier the category is nothing but a type of post so imagine if you’re creating a website like Alzato where your posts are related to movies and web series then you can make categories according to these. For example, action, adventure, thrill, horror, Netflix, Hotstar, Love story, teen,

comedy, etc. I hope you get the idea about adding a category to your website. 

Edit Category 
After that, you can find the option to edit the category. Imagine if you create a category as horror but you don’t have any post of horror type so you need to edit horror and some other categories that make sense to your website. To edit the category, you just need to click on the edit category where you’ll find options such as name, slug, parent category, and description. 

There you can easily change/edit the name of your category. A slug is nothing but a URL-friendly version of a name. You can change the parent category below and there’s a box to fill a description about the category. When you’re done just click on update and your category will be changed. 

Delete Category 
You can also find the delete option just beyond the edit category. You can delete a category by simply clicking the delete button and your category will be deleted. 

Arrange Category

You can also arrange categories of your post in wordpress. Although you can’t do it directly. To arrange the category of your post, you need to install a plugin for this. You can install a category order plugin for this from the add plugin option. After that, you will be able to arrange your categories in ascending and descending order.