When saving Microsoft Office documents, a lot of personal information like your user name, computer name, company name, date and time etc are stored in the documents properties.
Here is how to remove this from any of the Office document :
1. Right click on the document and select Properties.
2. Select Details and click on the Remove Properties And Personal Information link.
3. Select the Remove the following properties from this file and tick the fields that you want to remove, or simply click on Select All to remove all personal information.