Project Management is a process that helps in planning, organizing, and controlling the flow of resources and time in order to meet project goals. The Waterfall model is a sequential process where all activities are planned up front and then executed sequentially. The Agile model on the other hand is an iterative process where tasks are completed quickly with frequent feedback loops. The Waterfall model is popular among large organizations because it gives them predictability on how much time a project will take and how much it will cost. However, Agile has been gaining popularity in recent times because it helps companies get more done with less resources.