You can use OLTPRO to set up a direct debit when filing the Oklahoma state return.
Here are more options for taxpayers to pay their Oklahoma taxes:
Individual Income Tax Form 511-V.. If you have already filed your current year's individual income tax return, and are now wanting to send in your payment due for your Individual Taxes you must include the 511-V voucher with your payment.511-V Voucher Oklahoma Tax Commission Post Office Box 26890 Oklahoma City, OK 73126-0890
Electronic Funds Transfer System (EFT)/E-Check