Sometimes, we may have projects that have similar tasks e.g. maintaining social media campaigns for 15 clients. Besides creating a template (to save time when creating new projects) you can also copy tasks from one project to another.
Use the “Copy” link beneath each task and then select the project you want to copy it to.
Oh, and by the way, task copying is completely permission-based so that you can only copy tasks to projects that you are assigned to.