One question I regularly get asked is how to password protect, or encrypt a document in Microsoft Word, Excel or PowerPoint. The answer is actually surprisingly simple, and the same principle applies to both 2013 and 2010 versions. Here's how...
Open your document, and click the File button.
Choose Info from the File menu
Select Protect Document, then Encrypt With Password. Finally, choose a strong password for your document. If you need to inform someone else of your password to access a sensitive document, I would always recommend that you give the password verbally rather than in plain text over email.
Remember to make a note of your password, because if you lose it there is no way of recovering the document.
And that's it! Simple but effective.