The answer is at the top of the form: Attach to 1040 or 1040NR. There is no option for 1040A or 1040EZ. she has not paid any estimated tax for 2013 so far. --Is that a problem?) Not so far, but the first estimated 2013 tax payment is due April 15th. will she be required to make estimated tax payments in the future?If she has income for 2013, she should plan on meeting a safe harbor for state and federal 2013 income taxes.