Hi, I have just filed my state and federal returns via e-file. When I am sending my payment vouchers in mail, do I also need to send the returns in mail although I efiled

[Carl]

No. You only need to mail the vouchers with your payment. Since you owe taxes and they will be late, interest will be charged on the amount due. The interest stops accumulating on the date they actually receive your payment. The IRS will then bill you separately for any interest that may have accumulated. You generally have 30 days from the billing date to pay that interest, without accruing additional interest on the interest.