The Order Number is a unique alpha numeric field with a maximum of 25 characters. The order number is used throughout the system as the main unique identifier for a job; no two jobs can have the same order number.  The "Order Number" term can be changed to whatever your company uses (i.e. Work Order, WO#, MO#, etc.).  Order numbers can have a masked input.  You can change a job's order number after a job has been added to DMS as long as the order number is unique.  The Order Number term and optional mask is entered in Terms and Settings.