There are a few ways to get widescreen video.
The best way is with a widescreen camera: 16:9 chip/s.
Some cameras have 4:3 [square] chip/s but they can film in a type of widescreen by "reshaping" the imgage.
You can create widescreen in post with most middle to high end NLEs.
I'm guessing that you have a 4:3 camera if you are asking this question so the question is what camera are you using?
It could very well have a "widescreen" option.
I have an old Sony Digital8 single chip 4:3 and it gives me a "widescreen" setting but you really have to watch how you shoot composition wise because you will be cutting off much of the top and bottom.
Check this out:
http://blog.johnjosephbachir.org/guide-to-widescreen-in-video/