Shares
A share is a small piece of a company. Own one and you own a slice of everything it has and earns.
Where they trade
Shares of listed companies are bought and sold on a stock exchange, such as Milan, Frankfurt or Paris. You buy them through a broker: the bank or app that places the order for you. "Shares", "stocks" and "equities" mean the same thing here.
How you earn
Two ways. The price can rise, and you gain when you sell. Or the company can pay part of its profit to its owners in cash: a dividend.
Why the price moves
The price moves every second the exchange is open, because buyers and sellers keep changing their minds about what the company will earn in the future.
The risk
A company can shrink or fail, and then its shares can lose everything. That is why most people spread their money over many companies.