Item lists loop and create subworkflow

0

I would like to build a solution for incoming correspondence registration. Registering an envelope (which has its own barcode) and some fields, I would like to add some other barcodes in the Item Lists field and I would like a subworkflow (documents in an envelope) to be created for each of the lines. I can create a subworkflow, but I don't know how to loop through the Item Lists.
Do you have ideas how to do it?