ZipCode check on product details page will look as shown in image below.
Once you enter zipcode, you can see your zipcode is checked for COD for delivery are available or not for your entered zipcode. After entering zipcode site will not ask zipcode again.
If want to make some modifications in design of ZipCode control you can find it at Plug-ins → XcellenceIt.ZipCode → Views → ZipCode → ZipCodeCheck.html.
