You can decide whether you want to view your TaxJar Reports for California with tax collection estimates using either Modified Origin or Destination sourcing by editing the sourcing rules for the state in your State Settings.
The minimum requirement in CA is Modified-Origin, and by choosing this option, you, as the Seller, will end up leaving some responsibility on the customer to remit a use tax in addition to the minimum sales tax you charge. This is because Modified Origin sourcing means you won't be paying the state the full sales tax rate for each item you sold.
By selecting Destination sourcing for CA in your settings, the Expected Sales Tax Due Report will show the full rate you should have collected in all zip codes when you file so your customer isn’t on the hook to submit use tax to the state. (If you're selling via FBA, you should choose Destination sourcing in your Reports because this aligns with the way Amazon collects sales taxes in Calfornia for FBA sellers.)