I want to know if my iPhone X is been hack

By hack, if you mean remotely controlling your device, then...

Keep the iPhone updated to the latest iOS always and never Jailbreak. That's it.

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 Jailbreak
4. Don't share sensitive information pertaining to your device and payment methods
5. Beware of Phishing

Fabiancc Said:

"I want to know is my iPhone is been hack right now"

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Troubleshooting a "Hacked" iPhone:

Who's the Seller?:

If purchased form Apple, then no worries there. If you are concerned, reset this iPhone...

Setting this Up Anew:

If you wanted to, you could set it up anew, as if you were to sell it. All settings would be to default, and you would log in. From there, set this up as a child's phone.  Go Here: What to do Before you Sell, Give Away, or Trade in your iPhone, iPad, or iPod touch - Apple Support