Microsoft Outlook is part of Microsoft Office that you install on your PC or laptop. You set it up as a client to receive your email be it Exchange, POP3, IMAP, or you use the Hotmail Connector to get your Hotmail into Outlook. It is a suite of applications that work together that are installed locally on your PC. You can read more here: Microsoft Office Information
Outlook.com is the new Hotmail. Hotmail started out years ago as HoTMaiL - web-based HTML email. It evolved into Hotmail, became Windows Live, and has now been renamed to Outlook.com. This is confusing, but Outlook.com is simply just the new Hotmail. You can access it online or still use the Hotmail Connector to pull it into Microsoft Outlook.
If you currently have a Hotmail email address, you can go through the steps to convert it to an Outlook.com email address. It's very easy to do and the steps are presented to you one at a time. You can read more here: Outlook.com Information
Outlook 365 is essentially Outlook in the cloud. It is secure, anywhere access to Outlook, calendars, mail, etc. It's part of Office 365 and even includes file sharing. Here is a breakdown of Office 365:
To find out more about Office 365, you can go here: Office 365 Information
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