Notes and Custom fields are where the project manager can enter information that's important to the project, but is not needed by Project. These tabs on the Task Information dialog let you see and edit the Notes field and the defined task-level custom fields. Notes are used to capture information like detailed work instructions, or even simple status updates about the task. Custom fields are commonly used to capture information like the location of a task, or the name of the organization responsible for its completion.
Setting and Viewing Task Notes
Double-click on the task you want to edit.
Select the Notes tab.
Enter extra information about the task. This is commonly used as a place to store text-based details about the task.
Use the toolbar buttons to insert text, edit the font, justify the text, enter bulleted lists, or insert objects.
Click OK to save your changes.
Setting and Viewing Task Custom Fields
Select the Custom Fields tab.
This area lists any task custom field that has been customized in this project file. This tab provides a good consolidated view of all the task custom fields without having to insert them all into a view.
Edit the field in the Value field. Some fields might have drop-down lists for selecting from a predefined list of values.
Double-click on the task you want to edit. 
Select the Notes tab. 
Enter extra information about the task. This is commonly used as a place to store text-based details about the task. 
Use the toolbar buttons to insert text, edit the font, justify the text, enter bulleted lists, or insert objects. 
Click OK to save your changes. 
