The online Hollister promo code can be added once you are done shopping and ready to checkout. When you click your shopping cart you will be taken to the checkout screen. In the column to the right, under the order total, there is a space to enter the promo code.
Once the promo code is entered, it should be automatically applied to the cart items. If something is not working, there is an option to speak to a live person who can provide further assistance. Hollister promo codes usually come in sets of 6 digits. Each coupon has different exclusions and qualifications.