|Hey Id like to answer your question. Now that you've said what version of Office you are using, Im gonna be giving you a step by step guide to set up password for your document.|
1. Click on the review TAB on the menu bar
2. To the right hand corner you have a button which says protect document, just click on it
3. Click the first option Restrict formatting and editing
4. Now there's a side bar that appears with two options, just choose whatever option that you think is best. I would go for Editing Restriction as it prevents any unauthorized editing.
5. In the event that i select Editing Restrictions, Give a check mark in the check box and in the drop down select what type of restriction you would like to give.
6. Below this you have another check box that says EVERYONE, Give a check mark there too.
7. Now click on the button at the bottom which says Yes start Enforcing Protection.
8. Now you will be required to type in a password, make sure you remember what you type and try not to make it too complicated.
9. Remember to SAVE your document after this.
10. Now Close and try opening the file, the file will open but will be un-editable. In Office 2003 I remember having an option to trigger word to ask for a password to open a file. I'm not quite sure if that option exists in 2007. Anyways hope this helps
and in case you have issues just reply back. Thanks.