Yes. The Escrow Law requires that any person engaged in the escrow business as an escrow agent, Internet escrow agent or joint control agent within California may do so only as a corporation organized for that purpose licensed by the Commissioner as an escrow agent or joint control agent.
Escrow can be used for various transactions, including real estate, stock issuances, and online sales.
California Realtor here. Escrow is opened by the listing agent and 99% of the time the seller/listing agent chooses the escrow company. Escrow is opened once there's a contract.