Hi, thank you for your interest in air crafts. I can give you a short report on the pressurization system.
Cabin pressurization is the active pumping of air into an aircraft cabin to increase the air pressure within the cabin. It is required when an aircraft reaches high altitudes, because the natural atmospheric pressure is too low to allow people to absorb sufficient oxygen, leading to altitude sickness and ultimately hypoxia. Most turboprop aircraft also feature cabin pressurization due to their medium to high altitude operation. A very few piston-engined small private planes also do so; most do not routinely fly high enough to justify such a system.
Also in reply to your first question - I do not see any reason why a young enthusiastic pilot like you does not know that.