This license now allows you to get paid for your flying.  In general you must have an instrument rating along with this rating to fly for hire, but there are exceptions.  In many cases, people get their instrument and commercial ratings simultaneously. about one third of the pilot population have this rating.

The basic requirements for the rating are:

Hold at least a current private pilot certificate

Be at least 18 years of age

Be able to read, speak, write and understand the English language

Pass a computerized aeronautical knowledge  test

Pass a practical test

If training under Part 61, Title 14 of the Code of Federal Regulations (CFR) section 61.129, requires at least 250 hours of flight time, including 100 hours of pilot in command flight time, 50 hours of cross country flight time, and 10 hours of instruction in an airplane with a retractable landing gear and controllable pitch propeller.  There are additional requirements, but these are the basics.