If you are married as of the end of 2017, you have to file Married filing Jointly or Married filing Separately (and not as Single). In most cases, it is better to file jointly as you will end up paying less tax.
You can edit your info in the My Info of TurboTax. To edit, click on the pencil icon next to your name and change your marital status to Married. TurboTax will then asks for your spouse's info and asks if you wish to file jointly or separately.
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