Most businesses are not individuals but instead business entities such as corporations. This is because there are substantive liability protections as well as tax advantages to being "incorporated" as opposed to being "self-employed".
Most jurisdictions in the United States require that any business entity that is formed retain and maintain a "Registered Agent". This is also known as the “Resident Agent” depending on the laws of the individual jurisdiction the business entity is registered in. The purpose of a Registered Agent is to provide a legal address (not a PO Box) where there are persons available during all normal business hours to facilitate legal service of process being served in the event of a legal action or lawsuit. Generally, the registered agent is also where the state government sends all official documents required each year for tax and legal purposes such as franchise tax notices and annual reports. Registered Agents generally will also notify business entities if their state government filing status is in "Good Standing" or not. The reason that these notifications are a desired function of a registered agent is that it is difficult for a business entity to keep track of legislative changes and report due dates for multiple jurisidictions given the disparate laws of different states.
Penalties for not maintaining a registered agent generally will cause a jurisdiction to revoke a business’s corporate status as well as in some cases, assess additional penalty fees on the entity. If a Registered Agent fails to perform their function, it can have dire consequences for the business entity. For example, if a customer fell inside a store and sued the store, and the store's registered agent failed to notify the business entity of a summons to appear in court to respond to the lawsuit, then when the case went to trial, nobody would appear to defend the store and the customer would win by a default judgment. Additionally, the store would likely not be able to get the judgment overturned on appeal because they had been properly served.
Contractor University can act as your Resident Agent. Click here for fee schedule.