You can add, delete, or modify portfolio categories through the Portfolio > Portfolio Categories menu in your WordPress dashboard.
The grid filter will automatically display the categories created here, making it easy for visitors to sort and view your portfolio items by category.
It is recommended that each portfolio item has at least one category assigned to it.
You can also define parent and child categories for better organization of your work. However, please note that the grid filter does not currently support this configuration. As a result, parent and child categories will be displayed as separate items in the grid filter, rather than being nested under a single parent category.