Create New Categories

When creating a new post if you want to assign it to a new category you can create that category from your Dashboard. To do that go to: MainWP > Posts > Add New tab and on the right side of the page locate Categories metabox. There you have the option Add New Category. When you click that option, the field will appear:

In that field, write wanted category name and click Add New Category button. New category will appear in the list:

Select the new category, wanted child sites and click the Publish button and than new category will be created on your child sites.