You can see in top discounts tab, on click your previews discounts link list open.
You can see auto list all your discount code here, this link automatic apply your discount in cart.
Without show what you pass in url, you can apply discount in on going order.
Check generate icon in discount row at last, on click this app automatic generate all short links of this discount.
After generating list you can see different copy URL and view button in the same row for the copy short URL or view analytics result of this link..
If you want to see original URL with short URL, you need to click View button which is at the last, it will open detail page of this link.