For UK orders if you are not available when the item is ready to be delivered to you, the courier will leave a calling card or you will need to reach out directly to the courier to redirect your parcel.
This will give you options on how to retrieve your parcel. This is also updated on your tracking link with royal mail.
For international orders please contact your local post office if your order was shipped by post, DHL services or our customer service team if you need further assistance.