Yes, you can also create shipping labels and return labels in Pickware without an order, for example for spare parts, samples, or a return without an order. You can find the function in the Shopware Admin under Orders → Shipping labels: Click Create standalone shipping label or Create standalone return label.
In the dialog, you select a shipping method as a template or the carrier directly, enter the recipient, optionally from a customer address, and set up the packages with products or custom line items. This does not change your stock. You can then send a return label directly to the customer by email.
If such a label later turns out to belong to an order after all, you assign it to that order in the overview via Assign to order. The individual steps are described in How can I create shipping labels and return labels without an order?.