To-Dos differ from tasks in that they are often requests from other team members for assistance, as opposed to official task assignments by a project manager.
To-Dos vary as widely as your imagination
Some teams ask their users to use To-Dos like sticky notes all over Project Insight. You can add them to Projects, Tasks, Issues, stand alone in folders, and more.
If a longer task requires multiple steps, you can use multiple To-Dos to denote how far you have completed the task.
Anyone can assign To-Dos to another resource in Project Insight, so ask for help completing a task.