What Is Microsoft Teams?

Microsoft Teams is a chat-centered collaboration app within Microsoft 365 that combines persistent team chat, channel-based conversations, audio/video meetings, VoIP calling, and file collaboration in a single client. Unlike email, which is asynchronous and thread-per-message, Teams organizes conversations by team and channel so context persists and is searchable, and every channel is backed by a document library in SharePoint Online.

Teams' four pillars are chat (1:1 and group), channels (threaded, topic-based conversations inside a team), meetings (scheduled or ad hoc, with screen sharing, recording, and live captions), and calling (PSTN calling via Teams Phone when licensed). Each capability shares the same identity, presence, and notification system, so a chat can be escalated to a call with one click without switching apps.

Teams is not a standalone product but a front end over existing Microsoft 365 services: channel files live in SharePoint document libraries, chat files live in OneDrive, calendar and meetings sync with Exchange Online, and authentication runs through Microsoft Entra ID (formerly Azure AD). Creating a team automatically provisions a Microsoft 365 Group, a SharePoint site, and a shared mailbox behind the scenes.

Enterprises use Teams for internal collaboration and external guest access with partners; educational institutions use Teams for Education with assignments and class notebooks; and frontline organizations use Teams mobile with shift scheduling (via Shifts) for retail and healthcare workers who don't sit at a desk. The same core app adapts through licensing and app templates to each scenario.