Internet access is required to install and activate all Office 365 plans and to manage your subscription account. Internet connectivity is also required to access Office 365 cloud productivity services, including email, conferencing, IT management, and other services.
Many office 365 plans also include the desktop version of Office, for example, Office 365 small business premium and Office 365 enterprise E3. One of the benefits of having the desktop version of Office applications is that you can work offline and have the confidence that the next time you connect to the Internet all your work will automatically be synchronised, so you never have to worry about your documents being up to date. Your desktop version of Office is also automatically kept up to date and upgraded when you connect to the Internet, so you will always have the latest tools to help you work.
Office 365 is highly scalable and will support a one-person business to companies with tens of thousands of users:
Office 365 small business plans are best for companies with up to 10 employees, and can accommodate up to 25 users.
Office 365 midsize business is best for companies with 11 to 250 employees, and can accommodate up to 300 users.
Office 365 enterprise plans fit organizations ranging in size from a single employee to 50,000-plus users.