If you are legally separated according to the laws of your state then you can file your tax return as Single so his SSN is not needed.
If not, then you will have to file as Married Filing Separately.
The 2022 tax return can only be printed and mailed, it cannot be e-filed using TurboTax. When the Form 1040 is printed, on the first page, where the SSN for your spouse should be entered, write-in the word UNKNOWN.
Sign, date and mail your tax return.
If you are using TurboTax for tax year 2022, when asked for his SSN enter 999-88-9999. When the Form 1040 is printed, erase the number entered for the SSN and write-in UNKNOWN.
