I'm not sure about the electronic requirement, but all California tax-exempt organizations, including tax-exempt PTOs, must file from 199 (if your gross receipts are $25,000 or more) or 199n (for gross receipts under $25,000).
WHERE DO I GET, FORM 199N
Here's the link. You can file online. (Note that it's specifically for organizations that have official tax-exempt status.)
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