how do you create an apostrophe, but with letters? I'm having trouble on the web finding how to do it with letters instead of quotation, any help here?
Would a html entity code solve your problem? You can view them below http://unicode.e-workers.de/entities.php
For your case ' for '?
Update: Oh or do you mean the html tag TED<sup>x</sup> for sth like
TEDx
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/sub