Take a look at your actual CA tax forms in the section near the end that is labeled REFUND OR NO AMOUNT DUE. The mailing address may be shown right there.
The 2019 Form 540 for California shows the following address for mailing tax returns:
FRANCHISE TAX BOARD
PO BOX 942840
SACRAMENTO CA 94240-0001
There is nothing specific that you need to include in a cover letter. You are simply submitting a complete return for processing. Be sure to include copies of any W-2s or other necessary tax documents with the return.
... View more