An LLC with one member can choose to be treated as either a disregarded entity (sole proprietorship) or corporation for tax purposes, an LLC with more than one member can choose to be treated as either a partnership or a corporation for tax purposes. The default is disregarded entity or partnership (depending on whether the LLC has more than one member), and the election to be taxed instead as a corporation is made federally by filing with the IRS, the California tax treatment is based on how the LLC has chosen to be treated federally.

https://www.ftb.ca.gov/businesses/bus_structures/LLCompany.s...