iPhone 11 hacked

This does not indicate that your iPhone has been hacked. You have simply stumbled across a website that is trying to scam you.

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

iPhones can be hacked/infected, but this generally only happens to users who have jailbroken their device. The best way to keep your iPhone and online accounts secure is to regularly update iOS, use different passwords across websites, and learn to recognize scams.

Hi,

Do not worry!

It’s actually fake.

Here an answer written by a user on Apple Community on the same matter:

iOS / iPadOS devices cannot be hacked or infected with Virus / Malware / Spyware if it is updated to the latest iOS/iPadOS unless you have intentionally downloaded spurious software or unauthorized apps directly from the internet and installed on your device or/and have Jail Broken. 

It (Hacking) also depends on how careful are you in sharing sensitive and valuable information pertaining to your iPhone such as Passcode, Password etc with your friends and family members.

Be careful when sharing the device's sensitive and valuable information with friends and family members.

Thumb Rules:

1. Enable  Guided Access before handing over an iPhone to kids
2. Don't share Apple IDs
3. Don't Jail Break
4. Don't share sensitive information pertaining to your device and payment methods
5. Beware of Phishing

Full discussion here.

You can try to remove manually this message:

• Go to Settings and select Safari on the menu.
• Tap the Clear History and Website Data option.

If it doesn’t work:

• When on the Safari Settings screen, tap Advanced.
• Find the JavaScript entry - there and toggle it off. This should solve the problem.