Build a datatable finalDT which has all the columns that you need. Iterate through the datatable that you already have using For Each Datarow activity. Now use Add Datarow activity to add the row as an input array to the finalDT:
You can create a separate xaml and then add the data as argumnets and link the arguments according to thw columns that you have in the report…so that for each row you can send any combination from datatable columns and transaction item