It totally depends on where you are in the world. Every country has their own regulations.
There are many courses everywhere for as far as i am aware. The problem with herbal medicine is that a lot of it comes from ancient times. People had no other way than nature to cure them. They were completely dependent on shamans and bush doctors. Who abused this power in some cases and were not busy healing people at times, but more with enjoying the power. This has
led to the situation that there is a lot of contradictory information. One book will say herb X is good for disease Y, the other book will say it is good for disease Z.
Plants are very powerful, to chose the right course that is the problem. I would go for one that does make use of the traditional herbs that grow in your country, that have looked scientifically at what the helpful use is of those herbs, but one that also is open to the herbs of other countries, China for instance has a huge traditional herbal medicine tradition. The scientific research into herbs is limited everywhere, also in the west, because it takes a lot of money to do this research. Industrial medicine has no interest in clear information about the plant medicine because they want to
sell pills. Governments and universities sometimes will finance research, but it is limited.
If you want to help the people of your country you will have to have a more traditional approach because they will only be familiar with the
local plants and trust those to be helpful and you will be able to find them cheap or even grow them yourself, because plants are very much bound to local climates.
Once you have a good reputation you can start adding herbs from other places that people don't know.
If you are in the
city people will know less about local plants there it is easier to get them to be healed with "global" herbal medicine.
That is my idea about what you could do, i don't like doctors and western medicine, i try to live healthy and grow as many herbs as i can, but it's not a business, i have a very good book done by a passionate phyto therapist that uses as much scientific research as possible. I advice other people if they tell me what they have for herbal solutions, but i am no doctor. Just hobby.
Hope this answers some of your question!