Enter Customer Lot Numbers

Our customers provide our company with product to be processed through various manufacturing lines and return them once completed.

Most of the customers provide us with lot numbers that must be tracked through our processes and are required to appear on all paperwork (Order Confirmations, Invoices, and Packing Slips).

Is there any way to enter a customer's lot number when entering an order so that this information can be tracked besides entering the information into the "Comments/Instructions" section, which is how we currently enter this information. This however, leads to a lot of data entry, since it is required to be in both comments and instructions.