Opus 17, below, very correctly points out that a spouse's AGI isn’t required to e-file a tax return when you’re filing using the Married Filing Separately status.
[Edited 2/18/2021 | 7:04 am PST]
Your spouse's income is only needed on a separate return to test your qualifications for the premium tax credit ("Obamacare"). However, I'm not sure what happens if you leave it off. I don't believe it affects any other calculation.
Your spouse's AGI is NOT needed to e-file your tax return if you are filing Married Filing Separately.