Coaching is a professional service. Clients retain a coach in order to reach a goal or solve a problem.
Coaching works because the client gets the support he or she needs to make the desired change.
People hire a coach to make a change, reach a goal, solve a problem or take advantage of an opportunity.
Coaching has become so popular because people are far less willing to "settle" for the status quo. They are prepared to risk change in order to achieve more satisfying careers and lives.
Usually, clients already know what they want to change, resolve or accomplish, so the coaching begins right there. The coach will steer clients through a review of those goals and help develop an assessment of the real and imagined barriers that stand in the way of success.
Usually within a day or two, their attitudes will improve, or they'll get working on something they've been stuck with, or they'll make an important change and start feeling the benefits of coaching fairly quickly. Over time, the cumulative benefits can be life-changing.
Yes, most coaches give advice - or at least the coach can help you expand your options in a situation.