If you are legally married as of 12/31/2018 then you can only file your tax return as either Married Filing Jointly or Married Filing Separately. If you file as MFS then your spouse must also file as MFS. You both must use the Standard Deduction or you both must use Itemized Deductions when filing separately.
If you live in a community property state then the issue of filing separately gets more complex. See this TurboTax support FAQ for filing separately in a community property state - https://ttlc.intuit.com/questions/1901162-married-filing-separately-in-community-property-states
Note - If you have Not lived with your spouse at any time during the last six months of the year and you have a child as a dependent then you may be able to file as Head of Household if you meet the requirements. See this TurboTax support FAQ for Head of Household when married - https://ttlc.intuit.com/questions/2567672-can-a-married-person-claim-head-of-household-filing-status
If you are legally married as of 12/31/2018 then you can only file your tax return as either Married Filing Jointly or Married Filing Separately. If you file as MFS then your spouse must also file as MFS. You both must use the Standard Deduction or you both must use Itemized Deductions when filing separately.
If you live in a community property state then the issue of filing separately gets more complex. See this TurboTax support FAQ for filing separately in a community property state - https://ttlc.intuit.com/questions/1901162-married-filing-separately-in-community-property-states
Note - If you have Not lived with your spouse at any time during the last six months of the year and you have a child as a dependent then you may be able to file as Head of Household if you meet the requirements. See this TurboTax support FAQ for Head of Household when married - https://ttlc.intuit.com/questions/2567672-can-a-married-person-claim-head-of-household-filing-status