What are holding and closing notes used for?

Kelci, 

These are simply fields (textArea type) on the Project level that allow you to add notes to a project (separate from the related Notes Panel. These are fields that can be seen as a column on your Work Plan if so desired.

@Clarizen - We have a team lead who would like access to edit Holding Notes on all projects. It seems that field is locked and only editable by the Project Manager or Owner. Can I change edit permissions on this field or would I need to grant the team lead a different type of Clarizen access (if so which type)?

You would have to assign the user as a Manager to the work item (make sure multi-managers is enabled in settings to access the Managers field).