Pickware creates the invoice, delivery note, and the other order documents in the language of the customer or the order in Shopify. So you don't set the document language in Pickware; it is determined by the order. This also applies if you want to design your documents to be multilingual.

If documents appear in English instead of German, for example, this is usually due to the customer's language. Customers who were created before you changed the default language may still have English set as their language. In this case, change the preferred language on the customer.

To learn how else you can configure your order documents, see How do I configure and customize my order documents?