The best way to add or edit preferences is by using the defaults command.
plist file is located in the Data/Library/Preferences folder. For example, the app container for Outlook is named. The app container is located in the user's ~/Library/Containers folder. The app container is created the first time an app is run. Preference files are stored in the app container, which isn't the same thing as the app bundle. But, preference files aren't part of the app bundle for an app, so you can make changes to these files. This means that you can't customize the app bundle before or after you deploy Office.
To help improve security, Office for Mac has implemented Apple app sandboxing guidelines.