For each product and material, you can add a category for better tracking and identification purposes. On the product or material card, you can either select already existing categories or create new categories, but you cannot edit or delete existing categories.

You can edit or delete existing categories in the Settings menu:

1. Click on the "Settings" tab in the header.

2. Click on "Categories" in the left-hand menu.

To edit categories, click on the existing category name and edit the text field. Changes will be automatically applied to all products and materials using this category.

To delete a category, click on the trash bin icon next to a specific category. If a deleted category is used by a product or material, the category field for those items will then be empty.

To create a new category, click on the "+ Add new row" button and type a category name to the new field. This category is added to the category drop-down menu on item cards.