If you are creating Web pages for international audiences, you need to be aware of two issues:
Encoding. Web files can be encoded in a variety of formats; if you pick the wrong one, your text may be unreadable in certain languages or on certain browsers.
Character sets. In addition to specifying encoding, you need to specify the character set for which a browser should look when it displays text.
As long as you are creating Web pages purely for use in English-speaking locales, none of this is likely to be an issue. The default Western European encoding (officially called ISO-8859-1) does the job, as does the English/Western European/Other Latin Script character set that Word and Windows use ...