A profile in Outlook contains your email addresses, contacts, calendars, and preferences. You can have multiple addresses within one profile, or you can use your profiles to separate your different inboxes.
Note: Outlook 2010, and later versions, let you have multiple exchange addresses in a single profile.
Think of Outlook profiles like different user logins on a single computer. Each user has a desktop, different applications, and their own files and folders. Similarly, each Outlook profile has its own setup, and data.
Note: You can't switch Outlook profiles while Outlook is running.
Outlook will start with the default profile. You can set Outlook to prompt you for a profile when it starts.