Being a salesperson is being someone that knows everything that needs to be known in his field.
Salesperson basically sells the products of his company. It can be face to face or by phone.
They talk to a lot of people in order to sell them products.
There are a lot of places where salespeople can work at. It can be in a store, like Best Buy or Footlocker, or it can in a call center.
If you don't have any degree, you can easily apply at places like Best buy or Footlocker, but some places require at least a college degree or even a university degree.
It depends on witch company you work for. Usually, if you have a higher degree, like a university degree, you can be recruited at companies that pays really well.
The best training you can have as a sales person is field training. The more sales you do, the more adapted you'll become. It becomes really easy after that to make sales.
As a salesperson, you have to be able to always listen really well to the needs of the clients. If you get distracted and sell a product to a client that doesn't respond to his needs, he's not going to be satisfied. There are cases where the clients report employees who didn't correctly do their jobs, witch resulted in them losing their jobs. You have to be careful.
I don't think it's gonna happen anytime soon. A robot wouldn't be able to understand the needs of a client as well as a salesperson, because every client is different.
There isn't an age where you absolutely have to retire. As long as you do you job well, you can be a salesperson forever.
In conclusion, the job of a salesperson isn't for everyone and anyone. You absolutely have to like talking to people because this is all you're going to do as a salesperson.