Need to lock my account cause it's been hacked , what can I do about it ?

Check the troubleshooting steps in these related articles:

If you think your Apple ID has been compromised - Apple Support

Identify legitimate emails from the App Store or iTunes Store - Apple Support

I don't know what to do my account has been hacked

Why do you think your iPhone was hacked?

NO, if you haven't jailbroken your iPhone, it's not possible.

Additional check ⤵️

See who has access to your device or accounts

See who has access to your device or accounts – Apple Support (UK) 

Manage and use your Apple ID

Manage and use your Apple ID – Apple Support (UK)

Security and your Apple ID

Security and your Apple ID - Apple Support

Recognize and avoid phishing messages, phony support calls, and other scams

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

Create a strong password for your Apple ID, It is best if your password consists of eight or more characters and include upper and lowercase letters, and at least one number. You can also add extra characters and punctuation marks to make your password even stronger. 

Never provide your password, passcode, security questions, verification codes, recovery key or any other account security details to anyone else. Apple will never ask you for this information.