Microsoft Office 365 suite is a subscription service with the battle-tested Microsoft Office applications and essential collaboration tools like email, file storage, and instant messaging. A transition to Office 365 will be intuitive for companies with existing investments in Microsoft tools.
Google Apps for Business, now G Suite, is an alternative to Office 365. It offers many of the same collaboration and business software Office 365. Organizations with bring your own device (BYOD) policies may find G Suite easier to manage due to its web-based interface.