The link https://www.outlook.com/owa takes you to the Outlook sign in/sign up page. However, OWA here refers to Outlook Web Application, which was designed to serve the basic purpose of accessing mail from anywhere using the same functionality and UI of Outlook they are familiar with. Currently the https://www.outlook.com/owa has evolved to support all kind of browsers including the laptop, desktop, mobiles, as well as Mac computers. You are also provided with an option to sign up for Office 365 Customer Preview Enterprise or Small Business Premium for your business purposes. With OWA, you can access various tasks, contacts, documents, calendars, and more.