If you didn't remarry before the end of the tax year, you can file a joint return for yourself and your deceased spouse. When you're a surviving spouse filing a joint return and a personal representative hasn't been appointed, you should sign the return and write "filing as surviving spouse" in the signature area below your signature.
Refer to IRS FAQ Signing the return for additional information and the TurboTax article Death in the Family, Can I e-file a tax return for someone who is deceased?
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