There are "Display invoice number" and "Display packing slip number" settings. One of the options of these settings is "Order number", but when selected, the "document number" is displayed in the preview instead of the "order number".
If a document is generated for that order, when the selected option is "Order number", the document displays the order number correctly.
Also, the preview always displays the number that is displayed in the generated document.
There are "Display invoice number" and "Display packing slip number" settings. One of the options of these settings is "Order number", but when selected, the "document number" is displayed in the preview instead of the "order number".
If a document is generated for that order, when the selected option is "Order number", the document displays the order number correctly. Also, the preview always displays the number that is displayed in the generated document.