To be clear, the forms referenced in this question are submitted as part of a request for an installment agreement and not officially “filed”. Typically you complete an IRS Form 433-A when your client’s case has been assigned to a Revenue Officer (“RO”). In most of these cases you will negotiate directly with the RO and they will not require a 9465. A 9465 is more often used when requesting a streamlined installment agreement. That being said, the 9465 is a simple form to complete and therefore there is no harm in having it ready. You should also, prior to contacting the RO complete an IRS Form 433-D (Installment Agreement form) setting up automatic payments assuming you come to an agreement with the IRS. This may save an extra call which can take save you time and your client from paying additional fees.