State tax filing

Your post does not show an online version. I am going to assume you are using a desktop version.

You are correct, you must both itemize or both take the standard deduction. 

On the desktop version:

1. Switch to Forms Mode
2. On the left side, locate Info Worksheet
3. Scroll down to Part V and select the correct box
4. Switch back to step by step

Reference:

CA MFS/RDP instructions