Change Documents in SAP Project

In the Customising for Create Project Profile (OPSA) there are 2 fields for "Change Documents".

Where and how is this useful during implementation?

There are 2 outcomes for change documents and they should both be implemented if it's important that you keep track of changes made to a project:

General changes (the one at the top under Basic data) 

- any field content changes made to a project WBS after it was first saved will be recorded in a file. eg. if you changes the WBS description, the old value and the new value will be recorded, or if you changed a person responsible, it would also be recorded etc. This information can be reviewed in Info Systems report CN60 to old/new values and who/when.

Status Managment (the one under in Status Management) 

- any changes to System and User Status will be recorded, including the status history and who/when. Changes can be seen in any project maintenance transaction (eg. CJ02, CJ20N) by clicking on the "i" icon for a PD or WBS, then following the internal pull-down menu path: Extras>Change Documents> For Status/All.You can then drill-down on the satus to see its history.