In this tutorial I will explain you the step by step procedure with screenshots On How To Password Protect Microsoft Word 2007 Files
1. Click on the Microsoft Office Button present on the top left corner of the window.
2. Now Click on the Save As option
3. Now a new window will pop up.Click on Tools option at the bottom of the window.
4. Select General Options
5. Type the desired password you want
6. Click OK.
Hope it helps..