Microsoft Outlook supports multiple account types such as Microsoft Exchange Server, POP3, IMAP, and Outlook.com (formerly Hotmail).
Some features in Outlook require an Exchange account, which is provided by your organization, Microsoft Office 365, and some Internet hosting providers.
Check your account type in Outlook
In the main Outlook window, choose File > Account Settings > Account Settings.
On the Email tab, you'll see your accounts and the Type for each.
An Exchange account is listed as Microsoft Exchange.