For all, I believe you need a title.
As for licensing:
For most people the answer is "yes".
For farmers, loggers... who use it as part of their business, most of the time the answer is "no".
If you keep it on your own land, I believe you don't need to get a license for it.
Ahhh, found it.
Go to this site.
http://www.offroad-ed.com/mi/handbook/
Also check the MI DNR web site for getting the paperwork completed.