Sometimes  the person you are sending a document doesn't have the same font as you used in your document to make sure that the fonts in your document can be used by others, you will have to embed those fonts. Here is how to change the configuration to embed your fonts:

1. Click the Office button and then click Word Options.
2. MS Word opens the Word Options dialog box.
3. On the left side of the dialog box click Save.
4. Make sure the Embed Fonts in the File check box is selected.
5. To save on your file size, if you will be using only a small number of characters in a particular font (maybe a quote, or one word), choose the Embed Only the Characters Used in the Document check box.
6. To save space in the document, choose the Do Not Embed Common System Fonts check box.
7. Click on OK.
8. Work with your document as normal.

Embedding fonts will increase the size of your file (as the font file is built in)  In addition be aware not all fonts are embeddable, you may have to change the font.

I am double posting this on the Group Microsoft Office Tips as well.