Licensed agents or Brokers get paid a commission and annual renewals from the company/carrier. The Government mandates commission limits on Medicare Advantage Plans and Part D Rx plans. Individual States have limits on Medicare Supplement Commissions.
There are two main types of Agents, captive and non-captive agents. Captive Agents typically can only represent one company and can’t help you compare multiple plans side by side. In other words, they can only market one company. They often have sales quotas as well.
Non-Captive or Independent Agents (Brokers) can represent multiple companies and help you choose the best Medicare plan for you by offering a complete side by side comparison. A good agent will have competence and your best interest at heart at all times.
There are also agents that are only trained to represent Medicare Advantage Plans.  The commissions for these plans are usually double for the first year that someone is on a Medicare Advantage plan and overrides to their up-lines are larger than Medicare Supplement plans pay.
There is no charge to you to utilize a licensed Medicare certified agent. You can go it alone and call an 800 number and never get the same person or find a dedicated agent who should be competent and have only YOUR best interests in mind.