It can take several months for an installment agreement application to be approved by IRS and the monthly amounts to be deducted. They will send a letter via USMail once the plan is in place and the payments begin their schedule.
If you'd like to make payments toward the balance before that, you can mail them in by check with a 2016 1040V payment voucher, or use the online payments options at the IRS DIrectPay website.
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