Since you were still legally married on 12/31/2024 then you either file your tax return as Married Filing Jointly or Married Filing Separately.
If you have not lived with your spouse at any time during the last 6 months of the year and have a child as a dependent then you could file as Head of Household if you meet the requirements - https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/married-person-claim-head-household-filing-status/L078u1RSW_US_en_US?uid=m5zkzopt
Those are the same thing. You either file a Joint return or Married filing separately or Head of Household if you qualify. You can't file Single.
How should you file…..
https://turbotax.intuit.com/tax-tips/marriage/should-you-and-your-spouse-file-taxes-jointly-or-separately/L7gyjnqyM?srsltid=AfmBOopGqCNexowW0pYgvsf7ycIkrx4VjO_63UXv6vSnfu3UEGQiKQTh
If you have a child and lived apart for the last 6 months of 2024 you can file Head of Household.
Do you qualify for Head of Household?
https://ttlc.intuit.com/community/family/help/do-i-qualify-for-head-of-household/00/25539
Since you were still legally married on 12/31/2024 then you either file your tax return as Married Filing Jointly or Married Filing Separately.
If you have not lived with your spouse at any time during the last 6 months of the year and have a child as a dependent then you could file as Head of Household if you meet the requirements - https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/married-person-claim-head-household-filing-status/L078u1RSW_US_en_US?uid=m5zkzopt
Those are the same thing. You either file a Joint return or Married filing separately or Head of Household if you qualify. You can't file Single.
How should you file…..
https://turbotax.intuit.com/tax-tips/marriage/should-you-and-your-spouse-file-taxes-jointly-or-separately/L7gyjnqyM?srsltid=AfmBOopGqCNexowW0pYgvsf7ycIkrx4VjO_63UXv6vSnfu3UEGQiKQTh
If you have a child and lived apart for the last 6 months of 2024 you can file Head of Household.
Do you qualify for Head of Household?
https://ttlc.intuit.com/community/family/help/do-i-qualify-for-head-of-household/00/25539
The options are:
Married filing jointly. You can always file jointly if you both agree, and you may owe less tax that way, but there may be other complications.
Married filing separately. This is how you will file if you decide not to file jointly, and you don't qualify for single or head of household (below).
Head of household. You can file as HOH if you have been separated (living apart) for at least the last half of the year (since July 1, 2024) and you provide care in your home for at least one qualifying dependent, usually your child.
Single. The IRS says you can file single if you are "considered unmarried" because you are "Legally separated from your spouse under a divorce or separate maintenance decree." (And, "State law governs whether you are married or legally separated under a divorce or separate maintenance decree.")
I bring this up because it is in the rules, but no one actually qualifies. I have found several court cases where this was not allowed, and have not found a court case where it was allowed. The type of legal separation that might qualify went out of style in the 1950s or 1960s. The courts have ruled that it must be a final separation that can't legally be reversed (legally barred from reconciling even if you wanted to), and the support order has to be final (a temporary order during separation that will be finalized when the divorce is finalized doesn't count.). If you think you might qualify as "single" in your situation, see a local attorney for advice.