I'm going to assume you're talking about "white hat" hacking here., i.e. protecting your own systems or those of someone who has given you permission to do this. After all, computer crime is a federal offense in most states, and will bring a heat down on your head that WILL put you in a maximum security prison, or at the very least, a court order that you aren't to touch anything more sophisticated than a television for several years.
The short answer: a degree in Computer Science.
Long answer: You need to first understand how a computer works, the layers of the OSI model and basic networking. From there you need extensive experience using Linux and other UNIX systems - most of the internet runs on such systems. Several organisations (such as the IRS and even the US Airforce) still use Mainframe-style systems from decades ago because the cost of upgrading and replacing them would knacker their budget. You need to invest in TOR and VPN - specifically a VPN that doesn't keep records and accepts payments in cryptocurrency.
Finally, you need a whole *heap* of reference materials handy on computer security, standards and protocols, different 'NIX OS's, technical manuals, etc. You need to be willing to spend several hours a week reading up on new security flaws and bulletins. Learning to code is a must - that also requires a high level of logic and mathematical competence.
Above all, lose any hope of easy "point and click" hacking programs you haven't made yourself. Hackers call people who use such things "script kiddies" and often infest such programs with backdoors and trojans.