categories are classes or things which are related, and have some shared characteristics. the following steps describe how to add categories for the products in magento.
step 1 − login to your magento admin panel.
step 2 − go to the catalog menu and click on the manage categories option.
step 3 − next you need to fill the fields like name of the category, is active status which is set to yes/no and description of the category.
step 4 − click on save category button and your category is ready to have the products added to it.