On Hold

You can put any item on hold, perhaps because the budget isn’t approved, resources haven’t been hired, or you are just not ready to schedule the work.  When an item is on hold it isn't scheduled at all; so it's not pulling availability from anyone, and it isn't affecting any other work in your plan. 

You put an item on hold via the Options area within the edit pane. 

Putting a container (project, folder or package) on hold will put all items within that container on hold as well.  The items on hold will display the "on hold" icon in the left margin, and they will no longer have schedule bars:

 Don't miss these other scheduling options: setting a deadline date, setting a delay date, and setting the max effort for a plan item.