How can I add milestones in MS Project?

To add milestones in MS Project, go to the Gantt Chart view, select the task where you want to add a milestone, right-click on the task, and choose "Add Milestone." You can also change an existing task to a milestone by checking the "Mark Task as Milestone" box in the Task Information window. Milestones are important points in your project that signify a significant event or achievement.