Make promo code element visible
The cart or checkout pages are expected to have a promo code input.
A blank promo code/coupon box with a large Apply button can be quite confusing, making users wonder whether they should search for a code and potentially lead to lost conversions.[1]
However, users should notice this element without extra effort when scanning a page. Displaying a noticeable link allows designers to kill two birds with one stone. Firstly, it's easy to spot. Secondly, it only expands into an input on click and doesn't distract users who don't have a code or aren't interested in promotions.
