A Registered Agent is, as the Delaware Division of Corporations describes it, the agent every entity under 📝Delaware law must appoint to accept service of process; the Secretary of State of 📝California calls the role it requires an "agent for service of process."
The California Secretary of State states that corporations, limited liability companies, limited partnerships, and limited liability partnerships must by statute designate an agent for service of process. In California, according to the Secretary of State, that agent is "an individual who resides in California, or a registered 1505 corporate agent, designated to accept service of process (court papers) if the business entity is sued." The California Secretary of State says a business entity cannot act as its own agent for service of process, and that the agent's name and physical street address are a public record.
The Delaware Division of Corporations states that Delaware law requires every entity to appoint a Registered Agent with a physical office address in the State of Delaware. According to the Division, the Delaware requirements under 8 Del. C. § 132 are to maintain a street address and office in Delaware and to be open during normal business hours for the purpose of accepting service of process. The Division says Delaware Registered Agents accept service of process, forward it where applicable, and provide information for billing and tax obligations to the entities they represent. The Division states that a business physically located in Delaware may act as its own Registered Agent.