Custom Field

Hi,

A custom address field will be displayed when you're registering or when you're entering a new address or when you're editing an address.
If you're already logged in and already have an address, then the custom address field won't be displayed at all during the checkout.
So that's not what you want to use.
Instead, you want to create a custom field of the table "order" via the menu Display>Custom fields. Note that this is only possible with the Business edition of HikaShop.
The custom order fields will be displayed on your checkout by the "fields" view of your checkout workflow (that you can configure via the Checkout tab of the Hikashop configuration).

Hi,

If you want to do it for each product, you want to create a custom field of the table "item" (which requires HikaShop Business). In that case, the custom field will appear before the 'add to cart' button on the product details page. By default the custom field will appear for all the products, but you can restrict it to some products only thanks to the categories or the products restriction setting in the field settings page.

Hello,

This kind of mass actions settings will do the trick :

Hi,

Yes. You can use a filter "Category columns" in your mass action with the category_name column equal to the name of your category.
And in that case, the mass action will only apply to the products in that category.
Note that you can only specify one category. So you would have to run the mass action several times, changing the category name each time if you want to do it for several categories.