Since no human can see into the future, unfortunately new and experienced traders alike will sometimes have to contend with losing trades.
Financial markets are full of surprises, letting some get enormously rich while others (who are in majority unfortunately) lose all their capitals. But being patient and striving to perfect their skills many of those who lost in the very beginning still have their chance to become lucky millionaires someday.
Most major shares are traded on the stock market. This is a general term for a global network of specific exchanges where shares are bought and sold.