This User Login Activity Diagram depicts the login process of a system. It represents a series of actions or control flows. A use case diagram illustrates how methods work. Its illustration can also be done sequentially or concurrently. UML classified a login page system activity diagram as a very useful behavior diagram. This diagram depicts how the system and clients communicate with one another. This is accomplished by providing various levels of detail about the system's operation. When you use an activity diagram, you complete the major tasks that comprise the project's workflow. These things are determined by the user, which improves the interaction. It also demonstrates how login works.