Hello,
Because depending the context, the kind of custom field and the type of custom field ; our answer can be very different.
Kind of custom field : product custom field, item custom field, order custom field.
Type of custom field : text, calendar, radio, dropdown...
Context : product page, product listing, checkout, etc.
Now regarding your request, I recommend you to change the product quantity to "0" instead of hiding or showing the "add to cart" because it would still be possible to add the product in the cart.
Afterwards, if you want to perform a view override I recommend you that documentation page :
www.hikashop.com/support/documentation/1...-display.html#layout
And I would also recommend you the setting "display view files" but it's only available since HikaShop 3.1
It's a very useful feature when it comes to customization because it display the view names directly in the page ; so you can easily know which view you want to customize.
www.hikashop.com/support/documentation/5...g.html#advanced_main
Regards,