It depends what you seek in terms of goals/style/preferences. "Stocks" are usually the catch-all term used by the public for all types of financial securities from stocks themselves (also called equities) to options and currencies. Though I would say it is best to start with stocks as they are the easiest to learn, less volatile (compared to the others), and offer other benefits like dividends (which are payments given out to shareholders every quarter; but these are small stuff like 1%), although the downside is that it's not as easy to make a living with stocks with a small amount of money in a short time period (the other securities mentioned are better suited to that; although I wouldn't recommend). Thanks to technology it has never been cheaper/accessible to get into trading securities.
As for stocks themselves you can start right now by opening a account at any discount broker ( https://www.nerdwallet.com/blog/investing/the-best-discount-brokers/
) of your choosing. What broker you picks depends on your preferences; whether you are looking for cheap commissions (which is what you pay every transaction; but those usually dont go past $10) or tools they offer (some trading platforms which is what you use to analyze stocks and execute the orders themselves are more powerful/complicated than others) to finally requirements (some brokers require a certain minimum balance others do not). I personally use TD ameritrade which offers thinkorswim platform (referenced in meme-pic).
Once you open a account you can pick a stock and how many you want to buy and it's instantly executed if within the normal trading hours of the week. What you do next is up to you weather you decide to hold that stock for 10 years or 10 seconds (the latter is called day-trading, the former is investing). Most people when advising beginners tell them to just a buy a mutualfund/etf for the Dow/S&P (which gauges a picture of the market overall) and to leave it untouched, as they suggest against stock-picking. However if you are interested in stock-picking which requires more of your time but allows more flexibility…
The best strategy I recommend for beginners (as in what I personally started with) if you're insistent on stock-picking and not holdiPost too long. Click here to view the full text.