What are my options for my tax filing status for 2020? In 2019 I became separated, but not legally.

If you are legally married on 12/31/2019 and have lived with your spouse in the same household at any time in the last six months of the year then you can only file your 2019 tax return as either Married Filing Jointly or Married Filing Separately.

If, however, you did not live with your spouse at any time in the last six months of the year and you have a qualifying child as a dependent, provided over one-half the cost to maintain your home you may be eligible for Head of Household filing status.

See this TurboTax support FAQ for Head of Household when you are married - https://ttlc.intuit.com/community/married/help/can-a-married-person-claim-head-of-household-filing-status/01/26366