How to create WordPress categories
To create new categories in WordPress, you need to hover over the Posts then click Catgories page.
On the left side of the page you will see a tab that allows you to create categories. Fill in the category name, its slug (This will be the category URLs) decide if you want to add the category as a parent or child category to another and add a description of the category. Finally Add New Category. For the purpose of this tutorial we will make a new category called WordPress Training.
Now we deal with how to assign posts to categories
After you have created the category structure, you can add posts to categories. There are two ways you can do this. The first one is to open a post and place a checkbox in the category you want to assign it to. This will assign the specific post to the category.
The second way is to bulk add posts to a category. To do this go to Posts them All Posts. Next, select the posts you want to add to a category individually, click on the Bulk Actions tab, select Edit and finally press the Apply button.
You have a few options you can adjust for your posts. One of them is the Categories section. Select the category you want to add those posts to and click on the Update button. You can also bulk add a tag that you want here.