When you form your company at Firstbase.io, you are provided with a business address that is also a mail service. The mail service is included in the registered agent service (Cloud Peak Law).
Once Firstbase.io provides you with all the documents included in your Registration Package -- Certificate of Formation, Post-Formation documents, EIN letter -- your account will be transferred to the agent portal.
You should expect an email from the agent with the credentials to access this portal and, consequently, the mail service. After you log in to the agent portal, you will need to go to "Uploaded mail" to see the mails you have received and you can also forward them to your home address. Please notice you have 5 pieces of free mail scanning.