My husband did not file his 2023 tax return, how can I answer the question about his 2023 Tax return line 23600?

You can estimate what his Net Income would be. 

Are you sure that I should use just an estimate? I am worried that this would cause a problem on my file. 

Ask your husband for his Net Income so that you can enter it. He will need yours also. 

Thank you for choosing TurboTax.