If you filled in a 9465 when you filed the return the agreement should be in the PDF of the return if you save it with all the worksheets. It can take the IRS 6 weeks or more to agree or disagree with your proposed payment plan ... they will send you a letter in the mail either way. In the meantime you can make a payment online anytime : https://www.irs.gov/payments
Those vouchers say 2019 on them, right? Those are for making estimated payments towards 2019 so you don't owe money again. Do not use them to pay a 2018 tax balance.
Thank you for your help, now how do I go about getting vouchers for my 2018 payments? Or do I have to mail in the 9465 form first?
If you filled in a 9465 when you filed the return the agreement should be in the PDF of the return if you save it with all the worksheets. It can take the IRS 6 weeks or more to agree or disagree with your proposed payment plan ... they will send you a letter in the mail either way. In the meantime you can make a payment online anytime : https://www.irs.gov/payments
Can I make a payment without a voucher? I'm paying with a money order .
if using a MO you must mail it and use a voucher. otherwise you risk it getting lost. in any even make sure to put your ssn and tax year on MO.
Fill in and send this voucher with the payment : <a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/f1040v.pdf">https://www.irs.gov/pub/irs-pdf/f1040v.pdf</a>