You can apply a voucher or discount promo code to an order you placed in the past, in case that:

1. The promotion was active when the order was placed.
2. Your order is eligible for the promotion.
3. It’s been no more than 24h since you placed the order.

Just follow the instructions here: Apply a discount to my order

Important: In case the three conditions before are not met, unfortunately, we can’t apply the discount to your order.