Given how lucrative illegal hacking can be, there are black hat hackers for hire available online. However, you won't find them advertising their services on a professional website or listing their achievements on LinkedIn. The most common way to find a black hat hacker is through online forums, chat rooms, and the dark web.
Most also won't accept traditional payment methods like credit or debit cards. Instead, you'd be expected to pay with something less traceable. In many cases, this will be a pseudonymous cryptocurrency like Bitcoin. Even if they did offer card payments, it's probably unwise to trust a black hat hacker with your personal information.
Though, just because you can find black hat hackers online, doesn't mean that you should purchase their services. Even if you aren't performing the hack itself, you have initiated an illegal activity, making you party to the crime. Unless you are already experienced with criminal practices, you will often be easier for law enforcement to identify as well.
Popular sites like hackers24hrs, hirehacking, and thoriumhacks have prominent search result positions. However, reviews and comments elsewhere do not paint them as reputable services. Generally, if you want to hire a hacker to break into someone's account, install malware, or obtain sensitive information, this will not fall under white hat or ethical hacking.Email Hacking
Additionally, there is no guarantee or legal agreement once you hire a black hat hacker. There's always the possibility that they will take your money but fail to deliver the service. It's also likely that your target will be a person or organization you know or have been affected by. In which case, the hacker could find information with which to blackmail you. IPhone Hacking
Overall, we strongly recommend that you don't hire black hat hackers or involve yourself in illegal activity.