Copilot Studio is an end-to-end platform to build AI agents (chatbots / automation bots) for internal teams or external customers. You can design agents via a graphical (low-code) canvas or with natural-language prompts.

Power Apps is a suite of apps, services, connectors and a data platform that provides a rapid-development environment to build custom business apps without (much) coding. With Power Apps you can build custom business apps that connect to data stored in the underlying data platform (Microsoft Dataverse) or in many online or on-premises data sources (e.g. SharePoint, SQL Server, Microsoft 365, etc.).

Power Automate is a cloud-based service that makes it practical and simple for you to build workflows that automate time-consuming business tasks and processes across applications and services.

To use Power Automate, all you need are a web browser and an email address. Supported email addresses are described in the next question.

You can run Power Automate on all modern devices, and browsers.