To register your return digitally, you need your order number.
You can see this number at the top of the packing slip under the heading 'Order number'. You will find the packing slip in a plastic sleeve on the outside of your package.
You can also find the order number in the emails you received from us, like the order confirmation or the emails about the shipping status. In the emails, you can see the order number in the subject of the emails and at the bottom left of the emails about the shipping status.