PDF Order Center is an alternative to the default ZC order processing setup
in Admin::Customer::Orders for people who want to print PDF instead of HTML files.
Like the default setup, PDFOC allows you to update order status, optionally
including comments, optionally e-mailing the customer; delete an order; and print
an invoice or packing slip for an order. But PDFOC also allows you to:

      - process multiple orders at a time (batch processing)
      - print shipping labels
      - print price quotes and credit invoices
      - make minor customizations to the invoice format from the PDFOC control panel
      - create a unique, sequential invoice number for each order

And as the name implies, PDFOC creates PDF invoices, packing slips, etc. PDFOC
works with a template system, which allows you to easily add additional document
formats as desired.