The reservation can be book until 20 March 2022, and the JetBlue travel credit is good for one year from the date of issue of the tickets.
Travel credit is good towards JetBlue airfare only and can be applied to your new booking on the payment page of jetblue.com.
The buyer will receive my username and password in my JetBlue account to book the flights.
The amount can be use in more of one reservation. Only limitation is that they must be made before March 2022, and as metioned before and informed by JetBlue (buyer can verify it him/herself) after the reservation is made is valid for 1 year.