@NCperson The Form 1040 instructions indicate that the spouse's SSN is to be entered when filing as Married Filing Separately.
https://www.irs.gov/pub/irs-pdf/i1040gi.pdf#apge=12
Check the “Married filing separately” box at the top of Form 1040 or 1040-SR if you are married, at the end of 2022, and file a separate return. Enter your spouse’s name in the entry space below the filing status checkboxes. Be sure to enter your spouse’s SSN or Individual Taxpayer Identification Number (ITIN) in the space for spouse’s SSN on Form 1040 or 1040-SR.
