The question is a little vague, but I am going to assume you mean hack Google’s “backend” products, Gmail, Search, etc.

You are not likely to hack any of them. Google has a large well trained security team that monitors their network and is trying to keep nation state level attackers out, China, Russia, the NSA. All those agents would love to compromise Google (and probably do from time to time), but I doubt that they manage to hack Google consistently. But if Google can keep most of those players out most of the time. Unless you are really lucky, phenomenally lucky, you have no chance. The security team is continually looking for any signs of anomalous traffic and so all the common techniques for breaking in are well covered.

So, you need your own 0-day flaw in one of their networking appliances. You probably don’t even know what software and hardware they use. Your chances of doing so are effectively none. You could even study the hacking courses that are available and not be able to do it.

So, if you manage to actually hack Google’s network and steal data from them, you are likely to make a name for yourself among hackers. You are also eventually likely to get caught and prosecuted unless you work for a national security agency that wants your services and is willing to protect you from the laws.

The closest one can come to “hacking” Google is SEO (search engine optimization) which tries to guess what causes pages to rise to the top of Google search results. People have been trying to do that for years. Sometimes they are successful and get pages to rise to the top. But, then Google tweaks the algorithm and the hacks that worked stop working. From what I understand they now regularly tweak the engine just to make it harder for SEO to even have a chance of working.

Anyone that tries to sell you search engine optimization is preying on your gullibility. Just like hacking Google’s network, no one can do it consistently. They can promise that they do, but they are lying. Just like Google has a world class security team. Google has a world class team at tweaking their search algorithm to prevent SEO from being effective and they have had years of practicing it. Again, they have seen the best and keep checking. You are not going to beat them, not consistently. No one else is going to do so either.

If you mean something like hacking Google Chrome or Android or sending a Phishing Gmail or putting a virus in a YouTube video, those things are much easier, although even those are getting harder. But those aren’t hacking “Google”.