How do I add a user to a mailbox in Help Scout?

If you are an administrator of a Help Scout account, you may need to add a user to a mailbox in order to give them access to the mailbox and its contents. This could be necessary if you are adding a new team member to the account, or if you need to give someone access to a specific mailbox for a specific purpose. Knowing how to add a user to a mailbox in Help Scout is essential for managing your account and ensuring that the right people have access to the right resources.