Do I Need to Include Both Single Federal Returns or the Mock Return When Filing California State Taxes by Mail for a Registered Domestic Partnership?

[morg2019]

I'm filing my California state taxes for 2023. I'm in a registered domestic partnership, which requires me to file my state taxes by mail (as I’ve been told, e-filing isn’t an option). My partner and I filed our federal taxes separately as Single, dividing our income as community property. But, for the state return, we’re filing as Married Filing Jointly.

In the mail-in instructions, it says to include a copy of the federal return. To clarify, should I include both of our Single federal returns that we filed, or should I include the mock Married Filing Jointly federal return that I created for the state taxes? 

Thank you!

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