You can easily fill out the forms for the past fiscal year online here on eFile.com and sign them electronically before downloading, printing and sending them to the address listed below, depending on your residence in a state. Back taxes are also sent to the addresses listed below. You will find the postal addresses for tax changes via this link. A list of mailing addresses for 2019 tax returns. If you are not eligible for a payment plan through the online payment tool, you can still pay in installments. Your specific tax situation determines the payment options you have.