+1(514) 937-9445 or Toll-free (Canada & US) +1 (888) 947-9445
Anyone can apply so long as they are in Canada really. It’s your personal scenario that warrants H&C that will decide if you are approved or not.
 
You would have to have a very good reason for H&C if you are a US citizen. There are many other immigration programs that would be more applicable to most US citizens. I would you advise you speak to a Canadian immigration attorney.