Activity diagram is a flowchart that helps an analyst present concrete, easy-to-follow operational and business workflows. Activity diagrams are used in many situations, like creating use-case, business workflow, software protocol, and software algorithms. An activity diagram illustrates the steps involved in an activity and their order. Various functions can be accomplished using them, including modeling business processes and depicting control flows. Activity diagrams can be used whenever it is necessary to describe a behavior or to model control flows.