You can't e-file unless you make a payment arrangement. Either you chose "pay from my back account", "pay from a credit card", or "I will mail a check." If you selected the first two, payment will be made automatically. If you selected that you would pay by check, you can now either
a, print your tax return and take the voucher (form 1040-V) that prints out, add a check, and mail the check and the voucher to the IRS, or
b. make an electronic payment at www.irs.gov/payment
