In my country, before one begins the journey as an independent insurance agent, one must take an examination. That is the entry level.

Of course, you must choose which insurance organization you want to join first.  Then, you will need to find a sponsor. You will need to attend some classes organized by the insurance company.

After the exam, if one passes, there will be basic classes to attend. The sponsor will be busy teaching you all the skills you need to close deals. The insurance company will also grant you a license to act as an independent agent.

An independent agent can sell almost all types of policies offered by that particular insurance company.  

Maybe the system is different in other countries.