My son just realized he and his wife will owe $5000 on their joint taxes for
2022, due mainly to his wife starting a new job in 2022 and not calculating her exemptions correctly (i.e., under-withholding). They plan to file their return on time using online tax software, but would like to spread out the $5000 payment over several months. What options are available to set up a payment plan online, and what are the current interest rates/penalties they would need to pay?