Per IRS Instructions for Form 1040, starting on page 88:
Death of a Taxpayer. If a taxpayer died before filing a return for 2013, the taxpayer's spouse or personal representative may have to file and sign a return for that taxpayer. A personal representative can be an executor, administrator, or anyone who is in charge of the deceased taxpayer's property. If the deceased taxpayer did not have to file a return but had tax withheld, a return must be filed to get a refund. The person who files the return must enter "Deceased," the deceased taxpayer's name, and the date of death across the top of the return. If this information is not provided, it may delay the processing of the return.
If your spouse died in 2013 and you did not remarry in 2013, or if your spouse died in 2014 before filing a return for 2013, you can file a joint return. A joint return should show your spouse's 2013 income before death and your income for all of 2013. Enter "Filing as surviving spouse" in the area where you sign the return. If someone else is the personal representative, he or she must also sign.
The surviving spouse or personal representative should promptly notify all payers of income, including financial institutions, of the taxpayer's death. This will ensure the proper reporting of income earned by the taxpayer's estate or heirs. A deceased taxpayer's social security number should not be used for tax years after the year of death, except for estate tax return purposes.
Claiming a Refund for a Deceased Taxpayer. If you are filing a joint return as a surviving spouse, you only need to file the tax return to claim the refund. If you are a court-appointed representative, file the return and attach a copy of the certificate that shows your appointment. All other filers requesting the deceased taxpayer's refund must file the return and attach Form 1310.
To enter the death of a taxpayer or spouse in TaxACT: