Consulting can mean a lot of things - here - we mean B to B consulting relating to the running of a business. So this is not endowment consulting or a wealth management consultant. Typically, consulting firms are hired to solve a problem or review an activity at an organization with the intent to improve it.
Check out this video on what you do as a consultant:
Join the Consulting Club! In order to get most consulting roles, you will have what is called a "case interview." You have to prepare and practice in order to succeed in the interview process. The Consulting Club is the place for you to learn what they are, how to do them, and have a chance to develop and practice those interview skills.