She never made much but settled a divorce and ended up getting his retirement in 2018.  Aside from the penalty she owes a lot and her normal income cant pay what proseries is calculating her payments each quarter in 2019.  If she told me she could only pay... lets say $100 a quarter each quarter...does the IRS allow you to just make payments of however much you want or does she have to have this payment schedule approved by the IRS?