California defines a single member LLC as a "Disregarded Entity" because the single owner's income is treated as a Sole Proprietor on the Federal Schedule C Profit or Loss From Business (per the IRS instructions). While a single member LLC does not file California Form 565, they must file California Form 568 which provides details about the LLC.
Per the CA FTB Limited Liability Company (LLC) website:
If your LLC has one owner, you’re a single member limited liability company (SMLLC). If you are married, you and your spouse are considered one owner and can elect to be treated as an SMLLC. We require an SMLLC to file Form 568, even though they are considered a disregarded entity for tax purposes. They are subject to the annual tax, LLC fee and credit limitations.
To enter the information for Form 568 in the 1040 TaxAct® program:
Note. Schedule IW Limited Liability Income Worksheet, is included at the bottom of Form 568 which is used to populate the figure on Form 568, Line 1.
Note. TaxAct supports e-file for one copy of Form 568 in the 1040 product. Additional copies will need to be paper-filed.
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.