If my spouse has not completed his 2018 tax return yet, how do I answer that question?

[TurboTaxKim · Accepted solution]

If you are preparing your own tax return separately from your spouse and do not know what their net income is, you'll need to provide a reasonable estimate.

If your spouse's income is less than $11,809, you should prepare the returns together so you get any spousal credit or other transfers available to you.

https://turbotax.community.intuit.ca/replies/2647950