Data Type Yes/No (Yes/No field: A type of field with content set to either Yes or No; also known as a Boolean field or a True/False field. For example, the Recurring field indicates whether the task is a recurring task.)
Entry Type Entered (entered field: A field in which you may type or edit information. This is in contrast with a calculated field, in which Project calculates and enters information.)
Description The Marked task field indicates whether a task is marked for further action or identification of some kind. To mark a task, click Yes in the Marked field. If you don't want a task marked, click No.
Best Uses Use the Marked field to apply any Yes/No information to your tasks. Add the Marked field to a task view when you want to select certain tasks for viewing, filtering, formatting, or editing. You can mark tasks to specify special formatting for the Gantt Chart, the Calendar, or the Network Diagram views.
Example You need to identify certain tasks in order to track specialized accounting information. You add the Marked field and click Yes for each task that the special tracking applies to. You then filter on the Marked field to view and work with only those tasks marked Yes.
Remarks You can use the Marked field to apply text formatting, such as font style or color, only to tasks you have marked. Add the Marked field to a task sheet, and then click Yes for each task you want to mark. Then, in the Text Styles dialog box, make sure Marked Tasks is selected as the item to change, then change the font, color, or size. The changes you specified are applied to the marked tasks.