My phone just got hacked. How do I prevent this from people getting into my iCloud and information online or do I have to call?

It isn't real, ignore it you haven't been hacked.

It is a scam message designed to get you to purchase unnecessary software or phish for personal information. 

Read more about it here -

Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams - Apple Support

Your phone has NOT been hacked. You received a common Phishing Scam Message engineered to scare you into buying service/tools you don't need for an issue you don't have. Ignore and read this to learn about these messages --> Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams - Apple Support

The message that you saw is a common scam that is trying to trick you into tapping on a link to buy software that will be completely useless. It will however slow down your phone and put money in the pockets of the criminals who are trying to scam you.

Think about it. If your phone was really hacked.......why would the hacker tell you about this? They would want to keep it a secret and continue to use your personal and financial information.

If someone sent you a message that told you that a car was going to crash into your home unless you tapped on the link in the message.....would you believe it?

Ignore and delete the message. Do the same for other messages like this that you will receive.