protect word file with password ?

1. First open the word file we want to protect with password
2. Select Save as option
3. Select “tools” button ( top ) from save window
4. Then go to “general options”
5. there you can select password for the document ( see image )
6. Save the file to store the last changes
7. The next time when try to open the particular file a dialogue box will come to give password only giving that file will open