A registered agent is a person or company who is responsible for accepting official legal documents on behalf of a company. Every LLC is required by state law to have a registered agent with an office in the same state as the LLC is officially filed with. If you file to create your LLC in Delaware for example, then your LLC must have a registered agent in Delaware. If you additionally file a “foreign authorization” for your LLC to operate in another state, then your LLC must have another registered agent in that other state. So can an LLC have two registered agents?
An LLC can only have a single registered agent within a given state, and the name & address of that registered agent must be filed with that state. However, if an LLC operates in multiple states or operates in a different state than it is legally formed within, then the LLC must have a registered agent in each of those states.
However, within a single state, it is totally possible (and even recommended) for an LLC to hire a company rather than an individual to act as its registered agent and for that registered agent company to have two or more employees.
Your registered agent serves a very sensitive role for your company. A negligent registered agent can literally cost you thousands or even millions of dollars if someone files suit against your company, and your registered agent fails to notify you before a court passes default judgment. This is one of the reasons why it’s recommended to hire a company with multiple employees (i.e. so that if one person is sick or traveling, there is still someone there to forward any important legal correspondence to you immediately).
Unfortunately, most online registered agents are just people looking for easy money who use the same documents in every state even though different states actually have slightly different legal requirements. That can cause serious issues if your company is ever actually sued. Many will also try to upsell you on things like a “virtual office” and “mail forwarding” without making it clear that they are already legally obligated to forward any legal papers for your company. The virtual office is then just essentially an overpriced PO box for non-legal business mail, and it is probably not necessary for your company to purchase such services.