Currently it is possible to print a label for each line linked to, for instance, a purchase order. By using a query and specific criteria on the label layout data source, it is also possible to only include or exclude specific lines.

But in case the user should decide for which lines a label is required, it is not possible to print the label for a single or a selection of lines. It has good value to extent the functionality of custom labels to allow custom label printing on a line level within a document (currently only possible to show custom label print button on a header (e.g. purchase order, item arrival journal header, warehouse work header, etc.)).