Hello,

You can style your BizForm field control directly in UI of Kentico CMS in the same section where you have created the BizForm and where you are adding custom fields to your BizForm. Depending on the version of your Kentico CMS options to style the Field could be different, but at least you can assign some CSS class of directly CSS style to the field.

If you use the Control CSS class option, then you need to make sure that the page/document on which your BizForm sits is referencing some CSS stylesheet where such CSS class is defined.

Best regards,
Boris Pocatko