My checkout does not have an 'enter your coupon'

-- url of the page with the problem -- : www.melatoninznse.com/
-- HikaShop version -- : hikashop_essential_2.2.3
-- Joomla version -- : 12.2.0 Stable
-- PHP version -- : 5.3.24
-- Browser(s) name and version -- : Chrome latest build

Hi there can somebody help please? My site checkout does not have an 'enter your coupon' field. I have looked in the backend to try to enable one via "Hikashop->System->Configuration->Checkout" as I saw in another post but I do not see an applicable or appropriate option there to enable a coupon entry field. To clarify - I have made a coupon code, but I cannot make a blank field at the point of checkout to enable a customer to use the code. Thanks!

Thanks! This worked perfectly!