This is a PIN code. It is a special discount that can only be used by the person it is addressed to. It can be for a room only discount or free dining or some other type of package discount and would be good for a specified number of dates. These codes are different than the special offers for the general public. When, how, and why you might get a pin code is a bit of a mystery. You need to be in their system already. Perhaps by requesting a pre-planning video or creating an online account or doing online checks for reservations. Or by having already done a Disney vacation. I've gotten quite a few pins in recent years by email. They show up at irregular intervals, each with different offers for different dates. It's unpredictable. Other people I know (also WDW frequent visitors) have NEVER gotten a pin. As I say, it's a mystery.