Section 760 is the foundation of California's community property system and it is one sentence: except as otherwise provided by statute, all property, real or personal, wherever situated, acquired by a married person during the marriage while domiciled in this state is community property. Three features of that sentence decide most arguments about who owns what.
Acquisition during the marriage is the test — not whose name is on the title, not who paid, and not who earned the money. That is why a car, a pension contribution, a business interest or a rental property bought during the marriage from one spouse's salary is community property even though only one name appears anywhere: the salary itself was community property, and what it bought takes the same character. "Wherever situated" means a house in another state or another country is not outside the section. And "while domiciled in this state" is the geographical limit: property acquired while the couple lived elsewhere is not made community by this section, though the quasi-community property rules deal with much of it on a divorce in California.
The opening words, "except as otherwise provided by statute", carry a great deal of weight. Section 770 defines separate property — what was owned before marriage, and what was acquired during it by gift, bequest, devise or descent, together with the rents, issues and profits of that property. Section 771 makes earnings after the date of separation separate. Other statutes deal with transmutation between spouses, with community contributions to separate assets, and with reimbursement. Characterisation of a particular asset, especially one that was mixed or improved over time, is a technical exercise that regularly needs tracing evidence, and it belongs with a family lawyer.