We only offer it as a feature that can be enabled on your customer accounts. This allows you, as the operator, to offer registered agent services to your customers through the platform.
SphereMail itself does not act as a registered agent on behalf of your customers. So if your customer is looking for someone to serve as their registered agent, that would need to be handled on your end as the operator.
Consult this article here for more information on how to enable this service for your customers.