If you go to the Backstage view and select the Info option in the left column, you’ll see a Protect Document button in the middle of the window (by the Permissions heading). This button provides access to several tools you can use to help prevent unauthorized changes to your document and to help assure recipients of your document that it is indeed from you.
Here’s an overview of the options available from the Protect Document button:
Mark As Final
This command sets a flag in the file so that it opens in read-only mode. You can’t type in the document or edit it in other ways, and most buttons on the ribbon are disabled. This provides adequate protection from inadvertent changes, but it doesn’t defend against malicious changes. Anyone can remove the final status by revisiting the Info tab and clicking Mark As Final again or, more simply, clicking Edit Anyway in the message bar.
Encrypt With Password
When you choose this command, Word asks you to provide a password, which it then uses as a key for encrypting the document. Thereafter, Word asks for the password each time someone tries to open the document. Be sure you save the password in a safe place because there’s no practical way to recover it.
This command displays the Restrict Formatting And Editing task pane, which you can use to limit formatting changes and edits.
Restrict Permission By People
This command uses Information Rights Management (IRM) to keep track of which users are allowed to view or edit a document. If your network doesn’t have an IRM server, you can use a free online IRM service from Microsoft. Information about the service and a wizard for setting it up appear when you choose this command and you don’t already have an IRM server configured. After you configure the IRM service, you can specify which users have Read permission for the document and which ones have Change permission; people who aren’t on either list are prevented from opening the document. By clicking More Options in the Permission dialog box, you can set additional restrictions.
Add A Digital Signature
A digital signature is a code embedded in the document file that ensures that the document came from you (or someone who has access to the private key for your digital ID), and that the document hasn’t been altered. In addition, it provides a tamper-proof time stamp for the document. You can choose this command to learn about options for obtaining a digital ID if you don’t already have one.