• A put option is basically an insurance policy against the price of a particular stock going down (for people who want to sell that stock in the future).
• A call option is basically an insurance policy against the price of a particular stock going up (for people who want to buy that stock in the future).

In the US, the options (i.e., the insurance policies) have standardized terms, and can be bought, sold, and used through most online stock trading services.

Options are more like gambling than investing, and it is also much easier to lose large amounts of money. There are some legitimate uses for options, but they don't apply to 95% of the people reading this. Unless you understand very well how options work, you should treat it as similar to buying a lottery ticket or going to the casino and betting on dice:

• Spend only money you can afford to lose
• Realize you're probably doing business with someone who's mathematically proven that you'll lose money on average
• Realize that it's very easy to make very expensive mistakes
• Don't be surprised if you lose it all
• Consider it entertainment purposes only, not a strategy for reliably earning money