How to create password in Microsoft Excel or Ms office word or Powerpoint files in MS office 2007

These below steps are applicable to all Excel, doc, and ppt files.
1. open the document which you want to create password.
2. Now click office button in the left top side and Go to --> Prepare --> Encrypt document
3. A window will open, Enter the password and give enter.
4. Once again enter the password and give ok and then save the file.
5. Now if you open the file it will ask for password.