As a CAD technician/draughtsperson, you'll need to:
knowledge of engineering principles and ability to create and read technical drawings
Yes
Junior CAD technicians can progress to senior CAD technician roles, which can involve managing a team of technicians, overseeing work in the design office, and overall project management.
There are no entrance examinations for joining CAD/CAM courses. Many people are currently pursuing these courses in CIPET and other pioneered private institutions.