One method of encouraging customers to place and order is buy offering an discount. How could communicate that discount could be done in a coupon. Perhaps you email the customer a code or print it in a mail out there are various ways to do that but the piece that is being communicated is a code which is the coupon code. While this is common in POS scenarios you may want to also use this in sales orders which you can do as part of the call center functionality.
Here is a quick walk through.
AX2012 R3 Cu9.
While I’m using CU9 in this walk through, functionality was added in R3.