Microsoft Project Server and Project Online are enterprise Project Portfolio Management (PPM) tools. A Project Portfolio Management (PPM)tool is a tool that helps a company facilitate the process of organizing and managing collections of projects to achieve strategic goals. Both Project Server and Project Online store all project data in a consolidated database server, which provides ease of reporting and standardizes features and functionality. Project Server is an on-premise product that stores all data in a SQL Sever database. On-premise means that the server is physically located within a building at the company. Project Online is cloud-based product that stores all data in a Microsoft Azure database. Cloud-based means that the server is not physically located within a building at the company, instead, the server is owned and managed by a hosting company, in this case, Microsoft.
Project Web App (PWA) is the web-based user interface for both Project Server and Project Online. PWA is built on SharePoint technology. Anyone with the proper license can access PWA through a web browser, including project managers, schedulers, resource managers, executives and business leaders, application administrators, and other project team members. Application Administrators have the highest permission level within PWA and can maintain and configure the system.
Project Managers and Schedulers can connect the Microsoft Project desktop client to Project Web App (PWA), which allows them to use the features of either Project Sever or Project Online. Specifically, this allows them to save their Projects in the system database, to access and enter data into Enterprise Custom Fields, and to build their project team with Enterprise Resources.