You can pay the entire tax due in full when you file the return. However, you have the option to pay in three equal installments. If you choose to pay the tax due over three installments, the first installment is due July 10, 2018, the second is due August 10, 2018, and the third is due on September 10, 2018. The additional installments will be made electronically through the same process as the initial filing.