custom field on product page

I have created a custom field so a customer can select a certain style of my product. How do I get the custom field to show up on the product page?

Thanks

Turn on the "front end" option of the custom field.

OK, I have the custom fields showing up on the front end but on every product. How do I have them show only on certain products and not all?
Thanks

In the options of the field, you can restrict it to categories so that it won't show for other categories.