The LA Law Library (a county law library supported in part by civil filing fees in the LA County courts) maintains one of the most comprehensive collections of California Courts of Appeal briefs, dating back to California's admission to the Union and including selected digitized briefs from 1999 to the present. The collection continues to be digitized for online access, and the library will take requests for emailed/digitized briefs (provide the appellate case's docket number).
Many courts offer free access to electronic case information onsite at the courthouse (though there may be copy/download fees or limitations). For example:
Try to find any case-specific information (such as docket number, party name(s), filing dates, etc.) and contact the court's records department, clerk's office, or self-help center before visiting the court.
State court services for online access to docket sheets and underlying documents varies greatly from state to state and court to court.
Go to the individual county superior court's website (use the California court system's Find My Court page). In general, if the court makes docket sheets or the underlying documents available online, there will be a link under the "Online Services" tab on the home page—look for "Case Information," "Online Case Search" or similar wording. Practice varies widely, but some local examples include:
The Appellate Courts Case Information system allows you to search either the California Supreme Court or any of the state's six district Courts of Appeal, using the case (docket) number (including docket numbers from the lower courts involved in the appellate chain), or by case caption, attorney, or party information. Underlying filings and documents are not available.
For cases scheduled for oral argument Briefs of Argued Cases (including merits and amicus briefs) and related materials are available as PDFs—
Look for the state court system's site and check for an online "Case Information," "Case Lookup," "Filings," or similarly worded link.