Property managers vs handy man vs onsite PM - help me get it straight.

[Ceril S.]

I am a newbie just trying to get my terminology and job functions straight in my mind. 

Property Managers - when people refer to them, does that usually refer to a licensed company?  Could you hire an in-house property manager that is not licensed? Are there specific roles that they play? Signing leases, collecting rent?

Handy man - how does this differ from the property manager. If I go on vacation can I just leave a handyman on call or does that require a property manager?

On site - live in property manager or superintendent - do they need to be licensed?

Thanks for any help in clearing this up for me!