Registration form plus extra form for dimensions

Hi,

You can create form elements via the menu Display->Custom fields.
In the Starter edition, you can only create custom fields of the table "address". The fields will be displayed on the address form and attached to the addresses of the users.
With the Business edition, you can also create fields of the table "item" which would be displayed on the product page and attached to the product in the cart/order, or of the table "order" which would be displayed on the checkout page and attached to the order, or of the table "user" which would be displayed on the user registration form and attached to the user data.