...are the ownership shares of publicly traded corporations. There are thousands of stocks traded on dozens of stock exchanges around the world. As in any form of asset ownership, there are risks. Some companies pay dividends, others do not. Certain established "Blue Chip" stocks may be suitable for a client while new "Growth" or "Speculative" issue may not be appropriate. Before investing in any stock, an investor must investigate the company. There is no guarantee, of course, but a well informed buyer who understands the many variables of the stock market is not as dependent on "good luck" as one who is uninformed.
If you are not confident about your stock-picking skills, seek competent advice.