My husband is an inmate

If your husband is incarcerated, you may file a tax return either Married Filing Separately or Married Filing Jointly.  Either filing status is acceptable.  TurboTax will ask you if your husband was incarcerated during 2020 during the interview questions, and will take care of everything applicable.  Please note that If your husband has taxable income that he needs to report, then he should ask the authorities how to do so and to assist you in assisting him, if that is what you require.  This is important because not meeting a filing obligation can potentially complicate things, and the law does allow inmates to file tax returns.