If you were not legally married on 12/31/2023 you file your 2023 tax return as Single.
If you were still legally married on 12/31/2023 you can file as either Married Filing Jointly or Married Filing Separately. If you file as MFS you still need to enter your spouse's name and Social Security number on your tax return. Nothing further is required concerning your spouse unless you live in a community property state, then it becomes much more complex.
See this TurboTax support FAQ for filing separately in a community property state - https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/married-filing-separately-commu...
