Use Form 9465 to request a monthly installment plan if you cannot pay the full amount you owe shown on your tax return (or on a notice we sent you). Our comprehensive guide explains the purpose of Form 9465, how to fill it out correctly, and the steps to request an installment agreement.Use Form 9465 to request a monthly installment agreement (payment plan) if you can't pay the full amount you owe shown on your tax return. The IRS Online Payment Agreement system lets you apply and receive approval for a payment plan to pay off your balance over time. Request payment plan for any balances due. Do not ignore notices form the IRS. Letter 6475 helps EIP recipients determine if they're eligible to claim the Recovery Rebate Credit on their 2021 tax year returns. Please note payments mailed close to the first and second half due dates could take longer to post. Mail your payment to: Maricopa County Treasurer PO Box 52133 Request a Payment Plan. Help.