Hi,
Custom fields for products are there to enter custom information about products from the back end. Like, for example, when you have specifications for computers. It's not meant to be entered by the user on the front end but only displayed (and in the future filtered).
If you want the user to enter information for an order, you should create custom order filters. Those will be displayed on the checkout page and the user will be able to enter his information there. The information will then be attached to the order details and/or the order listing on the back end. That feature is only available on the Business version. Unfortunately, that doesn't enable you to set conditions on the custom fields.
Alternatively, we also have conditional custom fields in the business version of HikaShop. But they are on a dedicated page on the front end. We wrote a tutorial on them and we have a page on the demo website about them :
www.hikashop.com/en/support/documentation/75.html
That enables you to build a page where you can ask questions to the user as well as information and based on his answers, automatically add the corresponding products to the cart and redirect him to the checkout. That way, you could have your users buy more than one product in one order and use the product listing pages as information pages with the 'catalogue mode' to show to the user your catalogue of product. Then, the user would go to the entry page with a menu or with a custom link in the view. He would select a product with one custom field, select the option embroidery or not, and be asked for his name if he selected yes. Then, he would be able to add more products if he wants with again the same options available. Finally, he would be redirected to the checkout to complete his order. On your end, you would be able to see all the information he entered in the custom entry fields either in his order details or on the order listing.