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. An agreement you reach directly with the IRS to pay your federal tax due for a specific period of time is known as an IRS payment plan. Read your notice carefully. It explains how much you owe and your payment options. An IRS Installment Agreement is a provision that enables taxpayers to pay their outstanding tax liabilities through monthly payments. If the taxpayer contacts IRS and requests a Short Term Payment Plan within up to 180 days, see IRM 5.19.1.6. 3, Short Term Payment Plan Within 180 Days. Completing an online form and writing a signature on a computer.