Office 365 is a cloud-based software service from Microsoft that allows users to access applications like Word, Excel, and Outlook from any device, anywhere, with various subscription plans available. It offers enhanced security measures compared to traditional on-premises solutions, emphasizing data protection through encryption, multifactor authentication, and modular datacenters. Compared to its main competitor, Google Apps, Office 365 is seen as more versatile and secure, though it may require external assistance for migration and implementation.