When I write Powerpoint slides, I usually use title case for slide headers. I am a little unsure as to how to include e-commerce in headers. Wikipedia stylizes it as "E-commerce" which seems inelegant. Any guidance on how to use hyphenated words in titles?
Wikipedia does that to all its subjects. Don't take it seriously. The e in e-commerce comes from the e in eMail back when people still cared about e and i prefixes. They were always lower case. Capitalized as E-commerce it doesn't make me think of electronics or the internet. It makes me think of E! or Enron.
Some words respond to changing their capitalization well. This one doesn't.
e-Commerce evokes e-Mail which is old. e-mail is newer and email newest. Or laziest. What's best depends on whether you want to be formal or hip.