There are many different kinds of protection you can give to your Word 2010 document. You can protect your document in the following ways:
Encrypt With Password
You can make it so that anyone who wants to open a document has to supply a password. Click the File tab > Info > Protect Document (in the Permissions section) > Encrypt with password.
In the password window that opens, type in a password.
You will need to supply the password twice. Now, whenever someone tries to open the document, they will be presented with a password window similar to the one above. They will need to supply the correct password before they can see the document.
When a document has been protected this way, you will see the following in backstage view:
Mark as Final
Marking a document as final makes it read-only, so no changes can be made to it. This setting is advisory only. You can quite easily make the document available for further editing by reversing the steps outlined below. Marking as final indicates that editing is complete and that this is the final version of the document. Click the File tab > Info > Protect Document (in the Permissions section) > Mark as final. When the confirmation window is displayed, click OK.
Restrict style formatting
You can restrict the kinds of style formatting changes that can be made by clicking File > Info > Protect Document > Restrict Editing, and in the Formatting restrictions section, check the Limit Formatting to a selection of styles box.
If you then click Settings you will be able to select all the formatting styles that you want to be allowed (for example, Body Text, Heading 1, etc).
Similar to the above, click File > Info > Protect Document > Restrict Editing, and in the Editing restrictions section, check the Allow only this type of editing in the document.
If you select from the drop down list Tracked changes, Comments or Filling in forms, then only those kinds of edits will be allowed. If, instead, you select Read only then you can define exceptions – that is, areas of the document that can be edited. To do this, select a region to which you wish to allow editing, and then in the Exceptions section, select each user who should be given this privilege.
Restrict Open and Modify
You can prevent people opening and/or modifying a document by clicking the File tab > Save as > Tools > General options.
Enter a password into the Password to open box to restrict opening of the document and a password into the Password to modify box to… well you can guess.
If you found this tutorial interesting, you may find the How To Remove The Password From Word tutorial useful, too.