Office 365 is the brand name used by Microsoft for a group of software plus services subscriptions that provides productivity software and related services to its subscribers. For business and enterprise users, Office 365 offers plans including e-mail and business networking services through hosted versions of Exchange Server, Lync, SharePoint and Office Web Apps, integration with Yammer, as well as access to the Office software.

Microsoft Azure is a cloud computing service created by Microsoft for building, testing, deploying, and managing applications and services through a global network of Microsoft-managed data centers
Azure is an open, flexible, enterprise-grade cloud computing platform. Move faster, do more, and save money with IaaS + PaaS.

G Suite is a service from Google that provides independently customizable versions of several Google products using a domain name provided by the customer. It features several Web applications with similar functionality to traditional office suites, including Gmail, Google Calendar, Docs, Drive, Groups, News, Play, Sites, Talk, and Wallet.