8936 qualified plugin electric drive motor vehicle credit. I received a tax credit for a tesla model 3 on the federal, but why not on the california return

The tax credit is just for federal, California has a separate rebate that is not calculated on the tax return. 

Here is information from Tesla about the credits and rebates available for federal and by state: https://www.tesla.com/support/incentives

And here is where you can apply for the CA rebate if you are eligible: https://cleanvehiclerebate.org/eng