About product categories
Product categories can be modified via the edit product form.
1. Navigate to the edit form for the product (How do I edit a product?)
2. On the form that appears, under the Additional Details (Optional) heading, find the search box called Category. This is a box that will allow you to search for a category you already have in the system, or if this is a new category you can enter the name of it here.
3. Click the Save Product button to commit the changes.