Most people do not realize that when people collaborate on a Microsoft Office Word, Excel, or PowerPoint document, hidden information like deleted text, names of authors, and revision marks are sometimes unintentionally left in final drafts.
Remove hidden information from MS Office documents
The document Metadata can also spill the beans about your place of business: your company or organization's name, the name of the network server or hard drive on which the document is saved and any comments added.
Redact PDF or Word files
You can remove personal information from a document when you save it. In Word 2002 and 2003, click Tools, then Options. Click the Security tab. Under Privacy options, select "Remove personal information from file properties on save" and click OK.
Kim of USAToday recommends turning off Fast Save and the Track Changes tool to prevent MS Word from exposing sensitive information:
Microsoft Office plugin to Remove confidential information from Word Documents