What investment company do you think is the best?

I ask this because I get interested about the topic when I read that the actor Shia LaBeouf, for understand the investment world, before he started to act in a movie (Wall Street: Money Never Sleeps) related to the topic he invested $20,000 US in one of these companies and earned $300,000 US. Actually, is so simple to earn this money? It sounds like you could be a millionaire fastly. And for last, could you mention me websites that talk about this? Please!, if your an expert in this, say it. I will be thankful for your answer. Sorry if my English is no good.