I assume it's for your 2020 CA refund? Did you itemize deductions on your federal return for 2020? A State Tax Refund is taxable if you itemized deductions on that prior year's federal return and took a deduction for state income taxes instead of the sales tax. You got a deduction benefit for it so now you have to include it as income. If you took the Standard Deduction it is not taxable and you don't need to report it.
